147 changed files with 16670 additions and 40038 deletions
--- a/.github/workflows/github-actions.yml
+++ b/.github/workflows/github-actions.yml
@ -1,143 +0,0 @@
 name: MongoengineCI
 on:
  # All PR
  pull_request:
  # master branch merge
  push:
    branches:
      - master
  # release tags
  create:
    tags:
      - 'v[0-9]+\.[0-9]+\.[0-9]+*'
 env:
  MONGODB_3_6: 3.6.14
  MONGODB_4_0: 4.0.23
  MONGODB_4_2: 4.2
  MONGODB_4_4: 4.4
  PYMONGO_3_4: 3.4
  PYMONGO_3_6: 3.6
  PYMONGO_3_9: 3.9
  PYMONGO_3_11: 3.11
  MAIN_PYTHON_VERSION: 3.7
 jobs:
  linting:
    # Run pre-commit (https://pre-commit.com/)
    # which runs pre-configured linter & autoformatter
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2
    - name: Set up Python 3.7
      uses: actions/setup-python@v2
      with:
        python-version: 3.7
    - run: bash .github/workflows/install_ci_python_dep.sh
    - run: pre-commit run -a
  test:
    # Test suite run against recent python versions
    # and against a few combination of MongoDB and pymongo
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        python-version: [3.6, 3.7, 3.8, 3.9, "3.10", pypy3]
        MONGODB: [$MONGODB_4_0]
        PYMONGO: [$PYMONGO_3_11]
        include:
          - python-version: 3.7
            MONGODB: $MONGODB_3_6
            PYMONGO: $PYMONGO_3_9
          - python-version: 3.7
            MONGODB: $MONGODB_4_2
            PYMONGO: $PYMONGO_3_6
          - python-version: 3.7
            MONGODB: $MONGODB_4_4
            PYMONGO: $PYMONGO_3_11
    steps:
    - uses: actions/checkout@v2
    - name: Set up Python ${{ matrix.python-version }}
      uses: actions/setup-python@v2
      with:
        python-version: ${{ matrix.python-version }}
    - name: install mongo and ci dependencies
      run: |
        bash .github/workflows/install_mongo.sh ${{ matrix.MONGODB }}
        bash .github/workflows/install_ci_python_dep.sh
        bash .github/workflows/start_mongo.sh ${{ matrix.MONGODB }}
    - name: tox dry-run (to pre-install venv)
      run: tox -e $(echo py${{ matrix.python-version }}-mg${{ matrix.PYMONGO }} | tr -d . | sed -e 's/pypypy/pypy/') -- -a "-k=test_ci_placeholder"
    - name: Run test suite
      run: tox -e $(echo py${{ matrix.python-version }}-mg${{ matrix.PYMONGO }} | tr -d . | sed -e 's/pypypy/pypy/') -- -a "--cov=mongoengine"
    - name: Send coverage to Coveralls
      env:
        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        COVERALLS_SERVICE_NAME: github
      if: ${{ matrix.python-version == env.MAIN_PYTHON_VERSION }}
      run: coveralls
  build_doc_dryrun:
    # ensures that readthedocs can be built continuously
    # to avoid that it breaks when new releases are being created
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2
    - name: Set up Python ${{ matrix.python-version }}
      uses: actions/setup-python@v2
      with:
        python-version: 3.7
    - name: install python dep
      run: |
        pip install -e .
        pip install -r docs/requirements.txt
    - name: build doc
      run: |
        cd docs
        make html-readthedocs
  build-n-publish-dummy:
    runs-on: ubuntu-latest
    needs: [linting, test, build_doc_dryrun]
    if: github.event_name != 'pull_request'
    steps:
    - uses: actions/checkout@master
    - name: Set up Python 3.7
      uses: actions/setup-python@v1
      with:
        python-version: 3.7
    - name: build dummy wheel for test-pypi
      run: |
        pip install wheel
        python setup.py egg_info -b ".dev`date '+%Y%m%d%H%M%S'`" build sdist bdist_wheel
 #    - name: publish test-pypi
 #      # Although working and recommended, test-pypi has a limit
 #      # in the size of projects so it's better to avoid publishing
 #      # until there is a way to garbage collect these dummy releases
 #      uses: pypa/gh-action-pypi-publish@master
 #      with:
 #        password: ${{ secrets.test_pypi_token }}
 #        repository_url: https://test.pypi.org/legacy/
  build-n-publish:
    runs-on: ubuntu-latest
    needs: [linting, test, build_doc_dryrun, build-n-publish-dummy]
    if: github.event_name == 'create' && startsWith(github.ref, 'refs/tags/v')
    steps:
    - uses: actions/checkout@master
    - name: Set up Python 3.7
      uses: actions/setup-python@v1
      with:
        python-version: 3.7
    # todo separate build from publish
    # https://stackoverflow.com/questions/59349905/which-properties-does-github-event-in-a-github-workflow-have
    - name: build dummy wheel for test-pypi
      run: |
        pip install wheel
        python setup.py sdist bdist_wheel
    - name: publish pypi
      uses: pypa/gh-action-pypi-publish@master
      with:
        password: ${{ secrets.pypi_token }}
--- a/.github/workflows/install_ci_python_dep.sh
+++ b/.github/workflows/install_ci_python_dep.sh
@ -1,5 +0,0 @@
 #!/bin/bash
 pip install --upgrade pip
 pip install coveralls
 pip install pre-commit
 pip install tox
--- a/.github/workflows/install_mongo.sh
+++ b/.github/workflows/install_mongo.sh
@ -1,18 +0,0 @@
 #!/bin/bash
 MONGODB=$1
 # Mongo > 4.0 follows different name convention for download links
 mongo_build=mongodb-linux-x86_64-${MONGODB}
 if [[ "$MONGODB" == *"4.2"* ]]; then
  mongo_build=mongodb-linux-x86_64-ubuntu1804-v${MONGODB}-latest
 elif [[ "$MONGODB" == *"4.4"* ]]; then
  mongo_build=mongodb-linux-x86_64-ubuntu1804-v${MONGODB}-latest
 fi
 wget http://fastdl.mongodb.org/linux/$mongo_build.tgz
 tar xzf $mongo_build.tgz
 mongodb_dir=$(find ${PWD}/ -type d -name "mongodb-linux-x86_64*")
 $mongodb_dir/bin/mongod --version
--- a/.github/workflows/start_mongo.sh
+++ b/.github/workflows/start_mongo.sh
@ -1,9 +0,0 @@
 #!/bin/bash
 MONGODB=$1
 mongodb_dir=$(find ${PWD}/ -type d -name "mongodb-linux-x86_64*")
 mkdir $mongodb_dir/data
 $mongodb_dir/bin/mongod --dbpath $mongodb_dir/data --logpath $mongodb_dir/mongodb.log --fork
 mongo --eval 'db.version();'    # Make sure mongo is awake
--- a/.gitignore
+++ b/.gitignore
@ -1,15 +1,8 @@
 .*
 !.gitignore
 *~
 *.py[co]
 .*.sw[po]
 .cache/
 .coverage
 .coveragerc
 .env
 .idea/
 .pytest_cache/
 .tox/
 .eggs/
 *.egg
 docs/.build
 docs/_build
@ -20,6 +13,5 @@ env/
 .settings
 .project
 .pydevproject
 tests/test_bugfix.py
 htmlcov/
 venv
 venv3
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@ -1,26 +0,0 @@
 fail_fast: false
 repos:
  - repo: https://github.com/pre-commit/pre-commit-hooks
    rev: v4.0.1
    hooks:
      - id: check-merge-conflict
      - id: debug-statements
      - id: trailing-whitespace
      - id: end-of-file-fixer
  - repo: https://github.com/ambv/black
    rev: 21.5b2
    hooks:
      - id: black
  - repo: https://gitlab.com/pycqa/flake8
    rev: 3.9.2
    hooks:
      - id: flake8
  - repo: https://github.com/asottile/pyupgrade
    rev: v2.19.1
    hooks:
      - id: pyupgrade
        args: [--py36-plus]
  - repo: https://github.com/pycqa/isort
    rev: 5.8.0
    hooks:
      - id: isort
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@ -1,20 +0,0 @@
 # .readthedocs.yml
 # Read the Docs configuration file
 # See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
 # Required
 version: 2
 # Build documentation in the docs/ directory with Sphinx
 sphinx:
  configuration: docs/conf.py
 # Optionally set the version of Python and requirements required to build your docs
 python:
  version: 3.7
  install:
    - requirements: docs/requirements.txt
    # docs/conf.py is importing mongoengine
    # so mongoengine needs to be installed as well
    - method: setuptools
      path: .
--- a/.travis.yml
+++ b/.travis.yml
@ -0,0 +1,15 @@
 # http://travis-ci.org/#!/MongoEngine/mongoengine
 language: python
 python:
    - 2.5
    - 2.6
    - 2.7
    - 3.1
    - 3.2
 install:
    - if [[ $TRAVIS_PYTHON_VERSION == '2.'* ]]; then sudo apt-get install zlib1g zlib1g-dev; fi
    - if [[ $TRAVIS_PYTHON_VERSION == '2.'* ]]; then sudo ln -s /usr/lib/i386-linux-gnu/libz.so /usr/lib/; fi
    - if [[ $TRAVIS_PYTHON_VERSION == '2.'* ]]; then pip install PIL --use-mirrors ; true; fi
    - python setup.py install
 script:
    - python setup.py test
--- a/155
+++ b/155
@ -12,10 +12,12 @@ Laine Herron https://github.com/LaineHerron
 CONTRIBUTORS
-Derived from the git logs, inevitably incomplete but all of whom and others
+Dervived from the git logs, inevitably incomplete but all of whom and others
 have submitted patches, reported bugs and generally helped make MongoEngine
 that much better:
 * Harry Marr
 * Ross Lawley
 * blackbrrr
 * Florian Schlachter
 * Vincent Driessen
@ -23,7 +25,7 @@ that much better:
 * flosch
 * Deepak Thukral
 * Colin Howe
- * Wilson Júnior (https://github.com/wpjunior)
+ * Wilson Júnior
 * Alistair Roche
 * Dan Crosta
 * Viktor Kerkez
@ -75,7 +77,7 @@ that much better:
 * Adam Parrish
 * jpfarias
 * jonrscott
- * Alice Zoë Bevan-McGregor (https://github.com/amcgregor/)
+ * Alice Zoë Bevan-McGregor
 * Stephen Young
 * tkloc
 * aid
@ -104,7 +106,7 @@ that much better:
 * Adam Reeve
 * Anthony Nemitz
 * deignacio
- * Shaun Duncan
+ * shaunduncan
 * Meir Kriheli
 * Andrey Fedoseev
 * aparajita
@ -119,147 +121,4 @@ that much better:
 * Anton Kolechkin
 * Sergey Nikitin
 * psychogenic
- * Stefan Wójcik (https://github.com/wojcikstefan)
+ * Stefan Wójcik
 * dimonb
 * Garry Polley
 * James Slagle
 * Adrian Scott
 * Peter Teichman
 * Jakub Kot
 * Jorge Bastida
 * Aleksandr Sorokoumov
 * Yohan Graterol
 * bool-dev
 * Russ Weeks
 * Paul Swartz
 * Sundar Raman
 * Benoit Louy
 * Loic Raucy (https://github.com/lraucy)
 * hellysmile
 * Jaepil Jeong
 * Daniil Sharou
 * Pete Campton
 * Martyn Smith
 * Marcelo Anton
 * Aleksey Porfirov (https://github.com/lexqt)
 * Nicolas Trippar
 * Manuel Hermann
 * Gustavo Gawryszewski
 * Max Countryman
 * caitifbrito
 * lcya86 刘春洋
 * Martin Alderete (https://github.com/malderete)
 * Nick Joyce
 * Jared Forsyth
 * Kenneth Falck
 * Lukasz Balcerzak
 * Nicolas Cortot
 * Alex (https://github.com/kelsta)
 * Jin Zhang
 * Daniel Axtens
 * Leo-Naeka
 * Ryan Witt (https://github.com/ryanwitt)
 * Jiequan (https://github.com/Jiequan)
 * hensom (https://github.com/hensom)
 * zhy0216 (https://github.com/zhy0216)
 * istinspring (https://github.com/istinspring)
 * Massimo Santini (https://github.com/mapio)
 * Nigel McNie (https://github.com/nigelmcnie)
 * ygbourhis (https://github.com/ygbourhis)
 * Bob Dickinson (https://github.com/BobDickinson)
 * Michael Bartnett (https://github.com/michaelbartnett)
 * Alon Horev (https://github.com/alonho)
 * Kelvin Hammond (https://github.com/kelvinhammond)
 * Jatin Chopra (https://github.com/jatin)
 * Paul Uithol (https://github.com/PaulUithol)
 * Thom Knowles (https://github.com/fleat)
 * Paul (https://github.com/squamous)
 * Olivier Cortès (https://github.com/Karmak23)
 * crazyzubr (https://github.com/crazyzubr)
 * FrankSomething (https://github.com/FrankSomething)
 * Alexandr Morozov (https://github.com/LK4D4)
 * mishudark (https://github.com/mishudark)
 * Joe Friedl (https://github.com/grampajoe)
 * Daniel Ward (https://github.com/danielward)
 * Aniket Deshpande (https://github.com/anicake)
 * rfkrocktk (https://github.com/rfkrocktk)
 * Gustavo Andrés Angulo (https://github.com/woakas)
 * Dmytro Popovych (https://github.com/drudim)
 * Tom (https://github.com/tomprimozic)
 * j0hnsmith (https://github.com/j0hnsmith)
 * Damien Churchill (https://github.com/damoxc)
 * Jonathan Simon Prates (https://github.com/jonathansp)
 * Thiago Papageorgiou (https://github.com/tmpapageorgiou)
 * Omer Katz (https://github.com/thedrow)
 * Falcon Dai (https://github.com/falcondai)
 * Polyrabbit (https://github.com/polyrabbit)
 * Sagiv Malihi (https://github.com/sagivmalihi)
 * Dmitry Konishchev (https://github.com/KonishchevDmitry)
 * Martyn Smith (https://github.com/martynsmith)
 * Andrei Zbikowski (https://github.com/b1naryth1ef)
 * Ronald van Rij (https://github.com/ronaldvanrij)
 * François Schmidts (https://github.com/jaesivsm)
 * Eric Plumb (https://github.com/professorplumb)
 * Damien Churchill (https://github.com/damoxc)
 * Aleksandr Sorokoumov (https://github.com/Gerrrr)
 * Clay McClure (https://github.com/claymation)
 * Bruno Rocha (https://github.com/rochacbruno)
 * Norberto Leite (https://github.com/nleite)
 * Bob Cribbs (https://github.com/bocribbz)
 * Jay Shirley (https://github.com/jshirley)
 * David Bordeynik (https://github.com/DavidBord)
 * Axel Haustant (https://github.com/noirbizarre)
 * David Czarnecki (https://github.com/czarneckid)
 * Vyacheslav Murashkin (https://github.com/a4tunado)
 * André Ericson https://github.com/aericson)
 * Mikhail Moshnogorsky (https://github.com/mikhailmoshnogorsky)
 * Diego Berrocal (https://github.com/cestdiego)
 * Matthew Ellison (https://github.com/seglberg)
 * Jimmy Shen (https://github.com/jimmyshen)
 * J. Fernando Sánchez (https://github.com/balkian)
 * Michael Chase (https://github.com/rxsegrxup)
 * Eremeev Danil (https://github.com/elephanter)
 * Catstyle Lee (https://github.com/Catstyle)
 * Kiryl Yermakou (https://github.com/rma4ok)
 * Matthieu Rigal (https://github.com/MRigal)
 * Charanpal Dhanjal (https://github.com/charanpald)
 * Emmanuel Leblond (https://github.com/touilleMan)
 * Breeze.Kay (https://github.com/9nix00)
 * Vicki Donchenko (https://github.com/kivistein)
 * Emile Caron (https://github.com/emilecaron)
 * Amit Lichtenberg (https://github.com/amitlicht)
 * Gang Li (https://github.com/iici-gli)
 * Lars Butler (https://github.com/larsbutler)
 * George Macon (https://github.com/gmacon)
 * Ashley Whetter (https://github.com/AWhetter)
 * Paul-Armand Verhaegen (https://github.com/paularmand)
 * Steven Rossiter (https://github.com/BeardedSteve)
 * Luo Peng (https://github.com/RussellLuo)
 * Bryan Bennett (https://github.com/bbenne10)
 * Gilb's Gilb's (https://github.com/gilbsgilbs)
 * Joshua Nedrud (https://github.com/Neurostack)
 * Shu Shen (https://github.com/shushen)
 * xiaost7 (https://github.com/xiaost7)
 * Victor Varvaryuk
 * Stanislav Kaledin (https://github.com/sallyruthstruik)
 * Dmitry Yantsen (https://github.com/mrTable)
 * Renjianxin (https://github.com/Davidrjx)
 * Erdenezul Batmunkh (https://github.com/erdenezul)
 * Andy Yankovsky (https://github.com/werat)
 * Bastien Gérard (https://github.com/bagerard)
 * Trevor Hall (https://github.com/tjhall13)
 * Gleb Voropaev (https://github.com/buggyspace)
 * Paulo Amaral (https://github.com/pauloAmaral)
 * Gaurav Dadhania (https://github.com/GVRV)
 * Yurii Andrieiev (https://github.com/yandrieiev)
 * Filip Kucharczyk (https://github.com/Pacu2)
 * Eric Timmons (https://github.com/daewok)
 * Matthew Simpson (https://github.com/mcsimps2)
 * Leonardo Domingues (https://github.com/leodmgs)
 * Agustin Barto (https://github.com/abarto)
 * Stankiewicz Mateusz (https://github.com/mas15)
 * Felix Schultheiß (https://github.com/felix-smashdocs)
 * Jan Stein (https://github.com/janste63)
 * Timothé Perez (https://github.com/AchilleAsh)
 * oleksandr-l5 (https://github.com/oleksandr-l5)
 * Ido Shraga (https://github.com/idoshr)
--- a/CONTRIBUTING.rst
+++ b/CONTRIBUTING.rst
@ -1,109 +0,0 @@
 Contributing to MongoEngine
 ===========================
 MongoEngine has a large `community
 <https://raw.github.com/MongoEngine/mongoengine/master/AUTHORS>`_ and
 contributions are always encouraged. Contributions can be as simple as
 minor tweaks to the documentation. Please read these guidelines before
 sending a pull request.
 Bugfixes and New Features
 -------------------------
 Before starting to write code, look for existing `tickets
 <https://github.com/MongoEngine/mongoengine/issues?state=open>`_ or `create one
 <https://github.com/MongoEngine/mongoengine/issues>`_ for your specific
 issue or feature request. That way you avoid working on something
 that might not be of interest or that has already been addressed. If in doubt
 post to the `user group <http://groups.google.com/group/mongoengine-users>`
 Supported Interpreters
 ----------------------
 MongoEngine supports CPython 3.5 and newer as well as Pypy3.
 Language features not supported by all interpreters can not be used.
 Python3 codebase
 ----------------------
 Since 0.20, the codebase is exclusively Python 3.
 Earlier versions were exclusively Python2, and were relying on 2to3 to support Python3 installs.
 Travis runs the tests against the main Python 3.x versions.
 Style Guide
 -----------
 MongoEngine's codebase is auto-formatted with `black <https://github.com/python/black>`_, imports are ordered with `isort <https://pycqa.github.io/isort/>`_
 and other tools like flake8 are also used. Those tools will run as part of the CI and will fail in case the code is not formatted properly.
 To install all development tools, simply run the following commands:
 .. code-block:: console
    $ python -m pip install -r requirements-dev.txt
 You can install `pre-commit <https://pre-commit.com/>`_ into your git hooks,
 to automatically check and fix any formatting issue before creating a
 git commit.
 To enable ``pre-commit`` simply run:
 .. code-block:: console
    $ pre-commit install
 See the ``.pre-commit-config.yaml`` configuration file for more information
 on how it works.
 pre-commit will now run upon every commit and will reject anything that doesn't comply.
 You can also run all the checks with ``pre-commit run -a``, this is what is used in the CI.
 Testing
 -------
 All tests are run on `Travis <http://travis-ci.org/MongoEngine/mongoengine>`_
 and any pull requests are automatically tested. Any pull requests without
 tests will take longer to be integrated and might be refused.
 You may also submit a simple failing test as a pull request if you don't know
 how to fix it, it will be easier for other people to work on it and it may get
 fixed faster.
 General Guidelines
 ------------------
 - Avoid backward breaking changes if at all possible.
 - If you *have* to introduce a breaking change, make it very clear in your
  pull request's description. Also, describe how users of this package
  should adapt to the breaking change in docs/upgrade.rst.
 - Write inline documentation for new classes and methods.
 - Write tests and make sure they pass (make sure you have a mongod
  running on the default port, then execute ``python setup.py test``
  from the cmd line to run the test suite).
 - Ensure tests pass on all supported Python, PyMongo, and MongoDB versions.
  You can test various Python and PyMongo versions locally by executing
  ``tox``. For different MongoDB versions, you can rely on our automated
  Travis tests.
 - Add enhancements or problematic bug fixes to docs/changelog.rst.
 - Add yourself to AUTHORS :)
 Documentation
 -------------
 To contribute to the `API documentation
 <http://docs.mongoengine.org/en/latest/apireference.html>`_
 just make your changes to the inline documentation of the appropriate
 `source code <https://github.com/MongoEngine/mongoengine>`_ or `rst file
 <https://github.com/MongoEngine/mongoengine/tree/master/docs>`_ in a
 branch and submit a `pull request <https://help.github.com/articles/using-pull-requests>`_.
 You might also use the github `Edit <https://github.com/blog/844-forking-with-the-edit-button>`_
 button.
 If you want to test your documentation changes locally, you need to install
 the ``sphinx`` and ``sphinx_rtd_theme`` packages. Once these are installed,
 go to the ``docs`` directory, run ``make html`` and inspect the updated docs
 by running ``open _build/html/index.html``.
--- a/2
+++ b/2
@ -1,4 +1,4 @@
-Copyright (c) 2009 See AUTHORS
+Copyright (c) 2009-2012 See AUTHORS
 Permission is hereby granted, free of charge, to any person
 obtaining a copy of this software and associated documentation
--- a/README.rst
+++ b/README.rst
@ -4,78 +4,39 @@ MongoEngine
 :Info: MongoEngine is an ORM-like layer on top of PyMongo.
 :Repository: https://github.com/MongoEngine/mongoengine
 :Author: Harry Marr (http://github.com/hmarr)
-:Maintainer: Stefan Wójcik (http://github.com/wojcikstefan)
+:Maintainer: Ross Lawley (http://github.com/rozza)
-.. image:: https://travis-ci.org/MongoEngine/mongoengine.svg?branch=master
+.. image:: https://secure.travis-ci.org/MongoEngine/mongoengine.png?branch=master
-  :target: https://travis-ci.org/MongoEngine/mongoengine
+  :target: http://travis-ci.org/MongoEngine/mongoengine
 .. image:: https://coveralls.io/repos/github/MongoEngine/mongoengine/badge.svg?branch=master
  :target: https://coveralls.io/github/MongoEngine/mongoengine?branch=master
 .. image:: https://img.shields.io/badge/code%20style-black-000000.svg
  :target: https://github.com/ambv/black
 About
 =====
 MongoEngine is a Python Object-Document Mapper for working with MongoDB.
-Documentation is available at https://mongoengine-odm.readthedocs.io - there
+Documentation available at http://mongoengine-odm.rtfd.org - there is currently
-is currently a `tutorial <https://mongoengine-odm.readthedocs.io/tutorial.html>`_,
+a `tutorial <http://readthedocs.org/docs/mongoengine-odm/en/latest/tutorial.html>`_, a `user guide
-a `user guide <https://mongoengine-odm.readthedocs.io/guide/index.html>`_, and
+<http://readthedocs.org/docs/mongoengine-odm/en/latest/userguide.html>`_ and an `API reference
-an `API reference <https://mongoengine-odm.readthedocs.io/apireference.html>`_.
+<http://readthedocs.org/docs/mongoengine-odm/en/latest/apireference.html>`_.
 Supported MongoDB Versions
 ==========================
 MongoEngine is currently tested against MongoDB v3.4, v3.6 and v4.0. Future versions
 should be supported as well, but aren't actively tested at the moment. Make
 sure to open an issue or submit a pull request if you experience any problems
 with MongoDB version > 4.0.
 Installation
 ============
-We recommend the use of `virtualenv <https://virtualenv.pypa.io/>`_ and of
+If you have `setuptools <http://peak.telecommunity.com/DevCenter/setuptools>`_
-`pip <https://pip.pypa.io/>`_. You can then use ``python -m pip install -U mongoengine``.
+you can use ``easy_install -U mongoengine``. Otherwise, you can download the
-You may also have `setuptools <http://peak.telecommunity.com/DevCenter/setuptools>`_
+source from `GitHub <http://github.com/MongoEngine/mongoengine>`_ and run ``python
-and thus you can use ``easy_install -U mongoengine``. Another option is
+setup.py install``.
 `pipenv <https://docs.pipenv.org/>`_. You can then use ``pipenv install mongoengine``
 to both create the virtual environment and install the package. Otherwise, you can
 download the source from `GitHub <http://github.com/MongoEngine/mongoengine>`_ and
 run ``python setup.py install``.
 The support for Python2 was dropped with MongoEngine 0.20.0
 Dependencies
 ============
-All of the dependencies can easily be installed via `python -m pip <https://pip.pypa.io/>`_.
+- pymongo 2.1.1+
-At the very least, you'll need these two packages to use MongoEngine:
+- sphinx (optional - for documentation generation)
 - pymongo>=3.4
 If you utilize a ``DateTimeField``, you might also use a more flexible date parser:
 - dateutil>=2.1.0
 If you need to use an ``ImageField`` or ``ImageGridFsProxy``:
 - Pillow>=2.0.0
 If you need to use signals:
 - blinker>=1.3
 Examples
 ========
-Some simple examples of what MongoEngine code looks like:
+Some simple examples of what MongoEngine code looks like::
 .. code :: python
    from mongoengine import *
    connect('mydb')
    class BlogPost(Document):
        title = StringField(required=True, max_length=200)
-        posted = DateTimeField(default=datetime.datetime.utcnow)
+        posted = DateTimeField(default=datetime.datetime.now)
        tags = ListField(StringField(max_length=50))
        meta = {'allow_inheritance': True}
    class TextPost(BlogPost):
        content = StringField(required=True)
@ -95,52 +56,36 @@ Some simple examples of what MongoEngine code looks like:
    # Iterate over all posts using the BlogPost superclass
    >>> for post in BlogPost.objects:
-    ...     print('===', post.title, '===')
+    ...     print '===', post.title, '==='
    ...     if isinstance(post, TextPost):
-    ...         print(post.content)
+    ...         print post.content
    ...     elif isinstance(post, LinkPost):
-    ...         print('Link:', post.url)
+    ...         print 'Link:', post.url
    ...     print
    ...
    === Using MongoEngine ===
    See the tutorial
-    # Count all blog posts and its subtypes
+    === MongoEngine Docs ===
-    >>> BlogPost.objects.count()
+    Link: hmarr.com/mongoengine
    >>> len(BlogPost.objects)
    2
-    >>> TextPost.objects.count()
+    >>> len(HtmlPost.objects)
    1
-    >>> LinkPost.objects.count()
+    >>> len(LinkPost.objects)
    1
-    # Count tagged posts
+    # Find tagged posts
-    >>> BlogPost.objects(tags='mongoengine').count()
+    >>> len(BlogPost.objects(tags='mongoengine'))
    2
-    >>> BlogPost.objects(tags='mongodb').count()
+    >>> len(BlogPost.objects(tags='mongodb'))
    1
 Tests
 =====
 To run the test suite, ensure you are running a local instance of MongoDB on
-the standard port and have ``pytest`` installed. Then, run ``python setup.py test``
+the standard port, and run ``python setup.py test``.
 or simply ``pytest``.
 To run the test suite on every supported Python and PyMongo version, you can
 use ``tox``. You'll need to make sure you have each supported Python version
 installed in your environment and then:
 .. code-block:: shell
    # Install tox
    $ python -m pip install tox
    # Run the test suites
    $ tox
 If you wish to run a subset of tests, use the pytest convention:
 .. code-block:: shell
    # Run all the tests in a particular test file
    $ pytest tests/fields/test_fields.py
    # Run only particular test class in that file
    $ pytest tests/fields/test_fields.py::TestField
 Community
 =========
@ -148,7 +93,11 @@ Community
  <http://groups.google.com/group/mongoengine-users>`_
 - `MongoEngine Developers mailing list
  <http://groups.google.com/group/mongoengine-dev>`_
 - `#mongoengine IRC channel <irc://irc.freenode.net/mongoengine>`_
 Contributing
 ============
-We welcome contributions! See the `Contribution guidelines <https://github.com/MongoEngine/mongoengine/blob/master/CONTRIBUTING.rst>`_
+The source is available on `GitHub <http://github.com/MongoEngine/mongoengine>`_ - to
 contribute to the project, fork it on GitHub and send a pull request, all
 contributions and suggestions are welcome!
--- a/benchmark.py
+++ b/benchmark.py
@ -0,0 +1,199 @@
 #!/usr/bin/env python
 import timeit
 def cprofile_main():
    from pymongo import Connection
    connection = Connection()
    connection.drop_database('timeit_test')
    connection.disconnect()
    from mongoengine import Document, DictField, connect
    connect("timeit_test")
    class Noddy(Document):
        fields = DictField()
    for i in xrange(1):
        noddy = Noddy()
        for j in range(20):
            noddy.fields["key" + str(j)] = "value " + str(j)
        noddy.save()
 def main():
    """
    0.4 Performance Figures ...
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - Pymongo
    3.86744189262
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - MongoEngine
    6.23374891281
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - MongoEngine, safe=False, validate=False
    5.33027005196
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - MongoEngine, safe=False, validate=False, cascade=False
    pass - No Cascade
    0.5.X
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - Pymongo
    3.89597702026
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - MongoEngine
    21.7735359669
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - MongoEngine, safe=False, validate=False
    19.8670389652
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - MongoEngine, safe=False, validate=False, cascade=False
    pass - No Cascade
    0.6.X
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - Pymongo
    3.81559205055
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - MongoEngine
    10.0446798801
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - MongoEngine, safe=False, validate=False
    9.51354718208
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - MongoEngine, safe=False, validate=False, cascade=False
    9.02567505836
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - MongoEngine, force=True
    8.44933390617
    0.7.X
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - Pymongo
    3.78801012039
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - MongoEngine
    9.73050498962
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - MongoEngine, safe=False, validate=False
    8.33456707001
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - MongoEngine, safe=False, validate=False, cascade=False
    8.37778115273
    ----------------------------------------------------------------------------------------------------
    Creating 10000 dictionaries - MongoEngine, force=True
    8.36906409264
    """
    setup = """
 from pymongo import Connection
 connection = Connection()
 connection.drop_database('timeit_test')
 """
    stmt = """
 from pymongo import Connection
 connection = Connection()
 db = connection.timeit_test
 noddy = db.noddy
 for i in xrange(10000):
    example = {'fields': {}}
    for j in range(20):
        example['fields']["key"+str(j)] = "value "+str(j)
    noddy.insert(example)
 myNoddys = noddy.find()
 [n for n in myNoddys] # iterate
 """
    print "-" * 100
    print """Creating 10000 dictionaries - Pymongo"""
    t = timeit.Timer(stmt=stmt, setup=setup)
    print t.timeit(1)
    setup = """
 from pymongo import Connection
 connection = Connection()
 connection.drop_database('timeit_test')
 connection.disconnect()
 from mongoengine import Document, DictField, connect
 connect("timeit_test")
 class Noddy(Document):
    fields = DictField()
 """
    stmt = """
 for i in xrange(10000):
    noddy = Noddy()
    for j in range(20):
        noddy.fields["key"+str(j)] = "value "+str(j)
    noddy.save()
 myNoddys = Noddy.objects()
 [n for n in myNoddys] # iterate
 """
    print "-" * 100
    print """Creating 10000 dictionaries - MongoEngine"""
    t = timeit.Timer(stmt=stmt, setup=setup)
    print t.timeit(1)
    stmt = """
 for i in xrange(10000):
    noddy = Noddy()
    for j in range(20):
        noddy.fields["key"+str(j)] = "value "+str(j)
    noddy.save(safe=False, validate=False)
 myNoddys = Noddy.objects()
 [n for n in myNoddys] # iterate
 """
    print "-" * 100
    print """Creating 10000 dictionaries - MongoEngine, safe=False, validate=False"""
    t = timeit.Timer(stmt=stmt, setup=setup)
    print t.timeit(1)
    stmt = """
 for i in xrange(10000):
    noddy = Noddy()
    for j in range(20):
        noddy.fields["key"+str(j)] = "value "+str(j)
    noddy.save(safe=False, validate=False, cascade=False)
 myNoddys = Noddy.objects()
 [n for n in myNoddys] # iterate
 """
    print "-" * 100
    print """Creating 10000 dictionaries - MongoEngine, safe=False, validate=False, cascade=False"""
    t = timeit.Timer(stmt=stmt, setup=setup)
    print t.timeit(1)
    stmt = """
 for i in xrange(10000):
    noddy = Noddy()
    for j in range(20):
        noddy.fields["key"+str(j)] = "value "+str(j)
    noddy.save(force_insert=True, safe=False, validate=False, cascade=False)
 myNoddys = Noddy.objects()
 [n for n in myNoddys] # iterate
 """
    print "-" * 100
    print """Creating 10000 dictionaries - MongoEngine, force=True"""
    t = timeit.Timer(stmt=stmt, setup=setup)
    print t.timeit(1)
 if __name__ == "__main__":
    main()
--- a/benchmarks/test_basic_doc_ops.py
+++ b/benchmarks/test_basic_doc_ops.py
@ -1,142 +0,0 @@
 from timeit import repeat
 import mongoengine
 from mongoengine import (
    BooleanField,
    Document,
    EmailField,
    EmbeddedDocument,
    EmbeddedDocumentField,
    IntField,
    ListField,
    StringField,
 )
 mongoengine.connect(db="mongoengine_benchmark_test")
 def timeit(f, n=10000):
    return min(repeat(f, repeat=3, number=n)) / float(n)
 def test_basic():
    class Book(Document):
        name = StringField()
        pages = IntField()
        tags = ListField(StringField())
        is_published = BooleanField()
        author_email = EmailField()
    Book.drop_collection()
    def init_book():
        return Book(
            name="Always be closing",
            pages=100,
            tags=["self-help", "sales"],
            is_published=True,
            author_email="alec@example.com",
        )
    print("Doc initialization: %.3fus" % (timeit(init_book, 1000) * 10 ** 6))
    b = init_book()
    print("Doc getattr: %.3fus" % (timeit(lambda: b.name, 10000) * 10 ** 6))
    print(
        "Doc setattr: %.3fus"
        % (timeit(lambda: setattr(b, "name", "New name"), 10000) * 10 ** 6)  # noqa B010
    )
    print("Doc to mongo: %.3fus" % (timeit(b.to_mongo, 1000) * 10 ** 6))
    print("Doc validation: %.3fus" % (timeit(b.validate, 1000) * 10 ** 6))
    def save_book():
        b._mark_as_changed("name")
        b._mark_as_changed("tags")
        b.save()
    print("Save to database: %.3fus" % (timeit(save_book, 100) * 10 ** 6))
    son = b.to_mongo()
    print(
        "Load from SON: %.3fus" % (timeit(lambda: Book._from_son(son), 1000) * 10 ** 6)
    )
    print(
        "Load from database: %.3fus" % (timeit(lambda: Book.objects[0], 100) * 10 ** 6)
    )
    def create_and_delete_book():
        b = init_book()
        b.save()
        b.delete()
    print(
        "Init + save to database + delete: %.3fms"
        % (timeit(create_and_delete_book, 10) * 10 ** 3)
    )
 def test_big_doc():
    class Contact(EmbeddedDocument):
        name = StringField()
        title = StringField()
        address = StringField()
    class Company(Document):
        name = StringField()
        contacts = ListField(EmbeddedDocumentField(Contact))
    Company.drop_collection()
    def init_company():
        return Company(
            name="MongoDB, Inc.",
            contacts=[
                Contact(name="Contact %d" % x, title="CEO", address="Address %d" % x)
                for x in range(1000)
            ],
        )
    company = init_company()
    print("Big doc to mongo: %.3fms" % (timeit(company.to_mongo, 100) * 10 ** 3))
    print("Big doc validation: %.3fms" % (timeit(company.validate, 1000) * 10 ** 3))
    company.save()
    def save_company():
        company._mark_as_changed("name")
        company._mark_as_changed("contacts")
        company.save()
    print("Save to database: %.3fms" % (timeit(save_company, 100) * 10 ** 3))
    son = company.to_mongo()
    print(
        "Load from SON: %.3fms"
        % (timeit(lambda: Company._from_son(son), 100) * 10 ** 3)
    )
    print(
        "Load from database: %.3fms"
        % (timeit(lambda: Company.objects[0], 100) * 10 ** 3)
    )
    def create_and_delete_company():
        c = init_company()
        c.save()
        c.delete()
    print(
        "Init + save to database + delete: %.3fms"
        % (timeit(create_and_delete_company, 10) * 10 ** 3)
    )
 if __name__ == "__main__":
    test_basic()
    print("-" * 100)
    test_big_doc()
--- a/benchmarks/test_inserts.py
+++ b/benchmarks/test_inserts.py
@ -1,161 +0,0 @@
 import timeit
 def main():
    setup = """
 from pymongo import MongoClient
 connection = MongoClient()
 connection.drop_database('mongoengine_benchmark_test')
 """
    stmt = """
 from pymongo import MongoClient
 connection = MongoClient()
 db = connection.mongoengine_benchmark_test
 noddy = db.noddy
 for i in range(10000):
    example = {'fields': {}}
    for j in range(20):
        example['fields']["key"+str(j)] = "value "+str(j)
    noddy.insert_one(example)
 myNoddys = noddy.find()
 [n for n in myNoddys]  # iterate
 """
    print("-" * 100)
    print("PyMongo: Creating 10000 dictionaries.")
    t = timeit.Timer(stmt=stmt, setup=setup)
    print(f"{t.timeit(1)}s")
    stmt = """
 from pymongo import MongoClient, WriteConcern
 connection = MongoClient()
 db = connection.mongoengine_benchmark_test
 noddy = db.noddy.with_options(write_concern=WriteConcern(w=0))
 for i in range(10000):
    example = {'fields': {}}
    for j in range(20):
        example['fields']["key"+str(j)] = "value "+str(j)
    noddy.insert_one(example)
 myNoddys = noddy.find()
 [n for n in myNoddys]  # iterate
 """
    print("-" * 100)
    print('PyMongo: Creating 10000 dictionaries (write_concern={"w": 0}).')
    t = timeit.Timer(stmt=stmt, setup=setup)
    print(f"{t.timeit(1)}s")
    setup = """
 from pymongo import MongoClient
 connection = MongoClient()
 connection.drop_database('mongoengine_benchmark_test')
 connection.close()
 from mongoengine import Document, DictField, connect
 connect("mongoengine_benchmark_test")
 class Noddy(Document):
    fields = DictField()
 """
    stmt = """
 for i in range(10000):
    noddy = Noddy()
    for j in range(20):
        noddy.fields["key"+str(j)] = "value "+str(j)
    noddy.save()
 myNoddys = Noddy.objects()
 [n for n in myNoddys]  # iterate
 """
    print("-" * 100)
    print("MongoEngine: Creating 10000 dictionaries.")
    t = timeit.Timer(stmt=stmt, setup=setup)
    print(f"{t.timeit(1)}s")
    stmt = """
 for i in range(10000):
    noddy = Noddy()
    fields = {}
    for j in range(20):
        fields["key"+str(j)] = "value "+str(j)
    noddy.fields = fields
    noddy.save()
 myNoddys = Noddy.objects()
 [n for n in myNoddys]  # iterate
 """
    print("-" * 100)
    print("MongoEngine: Creating 10000 dictionaries (using a single field assignment).")
    t = timeit.Timer(stmt=stmt, setup=setup)
    print(f"{t.timeit(1)}s")
    stmt = """
 for i in range(10000):
    noddy = Noddy()
    for j in range(20):
        noddy.fields["key"+str(j)] = "value "+str(j)
    noddy.save(write_concern={"w": 0})
 myNoddys = Noddy.objects()
 [n for n in myNoddys] # iterate
 """
    print("-" * 100)
    print('MongoEngine: Creating 10000 dictionaries (write_concern={"w": 0}).')
    t = timeit.Timer(stmt=stmt, setup=setup)
    print(f"{t.timeit(1)}s")
    stmt = """
 for i in range(10000):
    noddy = Noddy()
    for j in range(20):
        noddy.fields["key"+str(j)] = "value "+str(j)
    noddy.save(write_concern={"w": 0}, validate=False)
 myNoddys = Noddy.objects()
 [n for n in myNoddys] # iterate
 """
    print("-" * 100)
    print(
        'MongoEngine: Creating 10000 dictionaries (write_concern={"w": 0}, validate=False).'
    )
    t = timeit.Timer(stmt=stmt, setup=setup)
    print(f"{t.timeit(1)}s")
    stmt = """
 for i in range(10000):
    noddy = Noddy()
    for j in range(20):
        noddy.fields["key"+str(j)] = "value "+str(j)
    noddy.save(force_insert=True, write_concern={"w": 0}, validate=False)
 myNoddys = Noddy.objects()
 [n for n in myNoddys] # iterate
 """
    print("-" * 100)
    print(
        'MongoEngine: Creating 10000 dictionaries (force_insert=True, write_concern={"w": 0}, validate=False).'
    )
    t = timeit.Timer(stmt=stmt, setup=setup)
    print(f"{t.timeit(1)}s")
 if __name__ == "__main__":
    main()
--- a/docs/Makefile
+++ b/docs/Makefile
@ -33,14 +33,8 @@ clean:
 html:
 	$(SPHINXBUILD) -b html $(ALLSPHINXOPTS) $(BUILDDIR)/html
 	@echo
 	@echo "Build finished. Check $(BUILDDIR)/html/index.html"
 html-readthedocs:
 	$(SPHINXBUILD) -T -E -b readthedocs $(ALLSPHINXOPTS) $(BUILDDIR)/html
 	@echo
 	@echo "Build finished. The HTML pages are in $(BUILDDIR)/html."
 dirhtml:
 	$(SPHINXBUILD) -b dirhtml $(ALLSPHINXOPTS) $(BUILDDIR)/dirhtml
 	@echo
--- a/docs/_themes/nature/static/nature.css_t
+++ b/docs/_themes/nature/static/nature.css_t
@ -0,0 +1,229 @@
 /**
 * Sphinx stylesheet -- default theme
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */
@import url("basic.css");
 /* -- page layout ----------------------------------------------------------- */
 body {
    font-family: Arial, sans-serif;
    font-size: 100%;
    background-color: #111;
    color: #555;
    margin: 0;
    padding: 0;
 }
 div.documentwrapper {
    float: left;
    width: 100%;
 }
 div.bodywrapper {
    margin: 0 0 0 230px;
 }
 hr{
    border: 1px solid #B1B4B6;
 }
 div.document {
    background-color: #eee;
 }
 div.body {
    background-color: #ffffff;
    color: #3E4349;
    padding: 0 30px 30px 30px;
    font-size: 0.8em;
 }
 div.footer {
    color: #555;
    width: 100%;
    padding: 13px 0;
    text-align: center;
    font-size: 75%;
 }
 div.footer a {
    color: #444;
    text-decoration: underline;
 }
 div.related {
    background-color: #6BA81E;
    line-height: 32px;
    color: #fff;
    text-shadow: 0px 1px 0 #444;
    font-size: 0.80em;
 }
 div.related a {
    color: #E2F3CC;
 }
 div.sphinxsidebar {
    font-size: 0.75em;
    line-height: 1.5em;
 }
 div.sphinxsidebarwrapper{
    padding: 20px 0;
 }
 div.sphinxsidebar h3,
 div.sphinxsidebar h4 {
    font-family: Arial, sans-serif;
    color: #222;
    font-size: 1.2em;
    font-weight: normal;
    margin: 0;
    padding: 5px 10px;
    background-color: #ddd;
    text-shadow: 1px 1px 0 white
 }
 div.sphinxsidebar h4{
    font-size: 1.1em;
 }
 div.sphinxsidebar h3 a {
    color: #444;
 }
 div.sphinxsidebar p {
    color: #888;
    padding: 5px 20px;
 }
 div.sphinxsidebar p.topless {
 }
 div.sphinxsidebar ul {
    margin: 10px 20px;
    padding: 0;
    color: #000;
 }
 div.sphinxsidebar a {
    color: #444;
 }
 div.sphinxsidebar input {
    border: 1px solid #ccc;
    font-family: sans-serif;
    font-size: 1em;
 }
 div.sphinxsidebar input[type=text]{
    margin-left: 20px;
 }
 /* -- body styles ----------------------------------------------------------- */
 a {
    color: #005B81;
    text-decoration: none;
 }
 a:hover {
    color: #E32E00;
    text-decoration: underline;
 }
 div.body h1,
 div.body h2,
 div.body h3,
 div.body h4,
 div.body h5,
 div.body h6 {
    font-family: Arial, sans-serif;
    background-color: #BED4EB;
    font-weight: normal;
    color: #212224;
    margin: 30px 0px 10px 0px;
    padding: 5px 0 5px 10px;
    text-shadow: 0px 1px 0 white
 }
 div.body h1 { border-top: 20px solid white; margin-top: 0; font-size: 200%; }
 div.body h2 { font-size: 150%; background-color: #C8D5E3; }
 div.body h3 { font-size: 120%; background-color: #D8DEE3; }
 div.body h4 { font-size: 110%; background-color: #D8DEE3; }
 div.body h5 { font-size: 100%; background-color: #D8DEE3; }
 div.body h6 { font-size: 100%; background-color: #D8DEE3; }
 a.headerlink {
    color: #c60f0f;
    font-size: 0.8em;
    padding: 0 4px 0 4px;
    text-decoration: none;
 }
 a.headerlink:hover {
    background-color: #c60f0f;
    color: white;
 }
 div.body p, div.body dd, div.body li {
    line-height: 1.5em;
 }
 div.admonition p.admonition-title + p {
    display: inline;
 }
 div.highlight{
    background-color: white;
 }
 div.note {
    background-color: #eee;
    border: 1px solid #ccc;
 }
 div.seealso {
    background-color: #ffc;
    border: 1px solid #ff6;
 }
 div.topic {
    background-color: #eee;
 }
 div.warning {
    background-color: #ffe4e4;
    border: 1px solid #f66;
 }
 p.admonition-title {
    display: inline;
 }
 p.admonition-title:after {
    content: ":";
 }
 pre {
    padding: 10px;
    background-color: White;
    color: #222;
    line-height: 1.2em;
    border: 1px solid #C6C9CB;
    font-size: 1.2em;
    margin: 1.5em 0 1.5em 0;
    -webkit-box-shadow: 1px 1px 1px #d8d8d8;
    -moz-box-shadow: 1px 1px 1px #d8d8d8;
 }
 tt {
    background-color: #ecf0f3;
    color: #222;
    padding: 1px 2px;
    font-size: 1.2em;
    font-family: monospace;
 }
--- a/docs/_themes/nature/static/pygments.css
+++ b/docs/_themes/nature/static/pygments.css
@ -0,0 +1,54 @@
 .c { color: #999988; font-style: italic } /* Comment */
 .k { font-weight: bold } /* Keyword */
 .o { font-weight: bold } /* Operator */
 .cm { color: #999988; font-style: italic } /* Comment.Multiline */
 .cp { color: #999999; font-weight: bold } /* Comment.preproc */
 .c1 { color: #999988; font-style: italic } /* Comment.Single */
 .gd { color: #000000; background-color: #ffdddd } /* Generic.Deleted */
 .ge { font-style: italic } /* Generic.Emph */
 .gr { color: #aa0000 } /* Generic.Error */
 .gh { color: #999999 } /* Generic.Heading */
 .gi { color: #000000; background-color: #ddffdd } /* Generic.Inserted */
 .go { color: #111 } /* Generic.Output */
 .gp { color: #555555 } /* Generic.Prompt */
 .gs { font-weight: bold } /* Generic.Strong */
 .gu { color: #aaaaaa } /* Generic.Subheading */
 .gt { color: #aa0000 } /* Generic.Traceback */
 .kc { font-weight: bold } /* Keyword.Constant */
 .kd { font-weight: bold } /* Keyword.Declaration */
 .kp { font-weight: bold } /* Keyword.Pseudo */
 .kr { font-weight: bold } /* Keyword.Reserved */
 .kt { color: #445588; font-weight: bold } /* Keyword.Type */
 .m { color: #009999 } /* Literal.Number */
 .s { color: #bb8844 } /* Literal.String */
 .na { color: #008080 } /* Name.Attribute */
 .nb { color: #999999 } /* Name.Builtin */
 .nc { color: #445588; font-weight: bold } /* Name.Class */
 .no { color: #ff99ff } /* Name.Constant */
 .ni { color: #800080 } /* Name.Entity */
 .ne { color: #990000; font-weight: bold } /* Name.Exception */
 .nf { color: #990000; font-weight: bold } /* Name.Function */
 .nn { color: #555555 } /* Name.Namespace */
 .nt { color: #000080 } /* Name.Tag */
 .nv { color: purple } /* Name.Variable */
 .ow { font-weight: bold } /* Operator.Word */
 .mf { color: #009999 } /* Literal.Number.Float */
 .mh { color: #009999 } /* Literal.Number.Hex */
 .mi { color: #009999 } /* Literal.Number.Integer */
 .mo { color: #009999 } /* Literal.Number.Oct */
 .sb { color: #bb8844 } /* Literal.String.Backtick */
 .sc { color: #bb8844 } /* Literal.String.Char */
 .sd { color: #bb8844 } /* Literal.String.Doc */
 .s2 { color: #bb8844 } /* Literal.String.Double */
 .se { color: #bb8844 } /* Literal.String.Escape */
 .sh { color: #bb8844 } /* Literal.String.Heredoc */
 .si { color: #bb8844 } /* Literal.String.Interpol */
 .sx { color: #bb8844 } /* Literal.String.Other */
 .sr { color: #808000 } /* Literal.String.Regex */
 .s1 { color: #bb8844 } /* Literal.String.Single */
 .ss { color: #bb8844 } /* Literal.String.Symbol */
 .bp { color: #999999 } /* Name.Builtin.Pseudo */
 .vc { color: #ff99ff } /* Name.Variable.Class */
 .vg { color: #ff99ff } /* Name.Variable.Global */
 .vi { color: #ff99ff } /* Name.Variable.Instance */
 .il { color: #009999 } /* Literal.Number.Integer.Long */
--- a/docs/_themes/nature/theme.conf
+++ b/docs/_themes/nature/theme.conf
@ -0,0 +1,4 @@
 [theme]
 inherit = basic
 stylesheet = nature.css
 pygments_style = tango
--- a/docs/apireference.rst
+++ b/docs/apireference.rst
@ -13,7 +13,6 @@ Documents
 .. autoclass:: mongoengine.Document
   :members:
   :inherited-members:
   .. attribute:: objects
@ -22,114 +21,54 @@ Documents
 .. autoclass:: mongoengine.EmbeddedDocument
   :members:
   :inherited-members:
 .. autoclass:: mongoengine.DynamicDocument
   :members:
   :inherited-members:
 .. autoclass:: mongoengine.DynamicEmbeddedDocument
   :members:
   :inherited-members:
 .. autoclass:: mongoengine.document.MapReduceDocument
-   :members:
+  :members:
 .. autoclass:: mongoengine.ValidationError
  :members:
 .. autoclass:: mongoengine.FieldDoesNotExist
 Context Managers
 ================
 .. autoclass:: mongoengine.context_managers.switch_db
 .. autoclass:: mongoengine.context_managers.switch_collection
 .. autoclass:: mongoengine.context_managers.no_dereference
 .. autoclass:: mongoengine.context_managers.query_counter
 Querying
 ========
-.. automodule:: mongoengine.queryset
+.. autoclass:: mongoengine.queryset.QuerySet
-    :synopsis: Queryset level operations
+   :members:
-    .. autoclass:: mongoengine.queryset.QuerySet
+   .. automethod:: mongoengine.queryset.QuerySet.__call__
      :members:
      :inherited-members:
-      .. automethod:: QuerySet.__call__
+.. autofunction:: mongoengine.queryset.queryset_manager
    .. autoclass:: mongoengine.queryset.QuerySetNoCache
      :members:
       .. automethod:: mongoengine.queryset.QuerySetNoCache.__call__
    .. autofunction:: mongoengine.queryset.queryset_manager
 Fields
 ======
-.. autoclass:: mongoengine.base.fields.BaseField
+.. autoclass:: mongoengine.BinaryField
-.. autoclass:: mongoengine.fields.StringField
+.. autoclass:: mongoengine.BooleanField
-.. autoclass:: mongoengine.fields.URLField
+.. autoclass:: mongoengine.ComplexDateTimeField
-.. autoclass:: mongoengine.fields.EmailField
+.. autoclass:: mongoengine.DateTimeField
-.. autoclass:: mongoengine.fields.EnumField
+.. autoclass:: mongoengine.DecimalField
-.. autoclass:: mongoengine.fields.IntField
+.. autoclass:: mongoengine.DictField
-.. autoclass:: mongoengine.fields.LongField
+.. autoclass:: mongoengine.DynamicField
-.. autoclass:: mongoengine.fields.FloatField
+.. autoclass:: mongoengine.EmailField
-.. autoclass:: mongoengine.fields.DecimalField
+.. autoclass:: mongoengine.EmbeddedDocumentField
-.. autoclass:: mongoengine.fields.BooleanField
+.. autoclass:: mongoengine.FileField
-.. autoclass:: mongoengine.fields.DateTimeField
+.. autoclass:: mongoengine.FloatField
-.. autoclass:: mongoengine.fields.ComplexDateTimeField
+.. autoclass:: mongoengine.GenericEmbeddedDocumentField
-.. autoclass:: mongoengine.fields.EmbeddedDocumentField
+.. autoclass:: mongoengine.GenericReferenceField
-.. autoclass:: mongoengine.fields.GenericEmbeddedDocumentField
+.. autoclass:: mongoengine.GeoPointField
-.. autoclass:: mongoengine.fields.DynamicField
+.. autoclass:: mongoengine.ImageField
-.. autoclass:: mongoengine.fields.ListField
+.. autoclass:: mongoengine.IntField
-.. autoclass:: mongoengine.fields.EmbeddedDocumentListField
+.. autoclass:: mongoengine.ListField
-.. autoclass:: mongoengine.fields.SortedListField
+.. autoclass:: mongoengine.MapField
-.. autoclass:: mongoengine.fields.DictField
+.. autoclass:: mongoengine.ObjectIdField
-.. autoclass:: mongoengine.fields.MapField
+.. autoclass:: mongoengine.ReferenceField
-.. autoclass:: mongoengine.fields.ReferenceField
+.. autoclass:: mongoengine.SequenceField
-.. autoclass:: mongoengine.fields.LazyReferenceField
+.. autoclass:: mongoengine.SortedListField
-.. autoclass:: mongoengine.fields.GenericReferenceField
+.. autoclass:: mongoengine.StringField
-.. autoclass:: mongoengine.fields.GenericLazyReferenceField
+.. autoclass:: mongoengine.URLField
-.. autoclass:: mongoengine.fields.CachedReferenceField
+.. autoclass:: mongoengine.UUIDField
 .. autoclass:: mongoengine.fields.BinaryField
 .. autoclass:: mongoengine.fields.FileField
 .. autoclass:: mongoengine.fields.ImageField
 .. autoclass:: mongoengine.fields.SequenceField
 .. autoclass:: mongoengine.fields.ObjectIdField
 .. autoclass:: mongoengine.fields.UUIDField
 .. autoclass:: mongoengine.fields.GeoPointField
 .. autoclass:: mongoengine.fields.PointField
 .. autoclass:: mongoengine.fields.LineStringField
 .. autoclass:: mongoengine.fields.PolygonField
 .. autoclass:: mongoengine.fields.MultiPointField
 .. autoclass:: mongoengine.fields.MultiLineStringField
 .. autoclass:: mongoengine.fields.MultiPolygonField
 .. autoclass:: mongoengine.fields.GridFSError
 .. autoclass:: mongoengine.fields.GridFSProxy
 .. autoclass:: mongoengine.fields.ImageGridFsProxy
 .. autoclass:: mongoengine.fields.ImproperlyConfigured
 Embedded Document Querying
 ==========================
 .. versionadded:: 0.9
 Additional queries for Embedded Documents are available when using the
 :class:`~mongoengine.EmbeddedDocumentListField` to store a list of embedded
 documents.
 A list of embedded documents is returned as a special list with the
 following methods:
 .. autoclass:: mongoengine.base.datastructures.EmbeddedDocumentList
    :members:
 Misc
 ====
 .. autofunction:: mongoengine.common._import_class
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@ -1,722 +1,40 @@
 =========
 Changelog
 =========
-Development
+Changes in 0.7.X
 ===========
 - (Fill this out as you fix issues and develop your features).
 - EnumField improvements: now `choices` limits the values of an enum to allow
 - Fix deepcopy of EmbeddedDocument #2202
 - Fix error when using precision=0 with DecimalField #2535
 - Add support for regex and whole word text search query #2568
 Changes in 0.23.1
 ===========
 - Bug fix: ignore LazyReferenceFields when clearing _changed_fields #2484
 - Improve connection doc #2481
 Changes in 0.23.0
 =================
- Bugfix: manually setting SequenceField in DynamicDocument doesn't increment the counter #2471
+- Added NotUniqueError for duplicate keys (MongoEngine/mongoengine#62)
- Add MongoDB 4.2 and 4.4 to CI
+- Added custom collection / sequence naming for SequenceFields (MongoEngine/mongoengine#92)
- Add support for allowDiskUse on querysets #2468
+- Fixed UnboundLocalError in composite index with pk field (MongoEngine/mongoengine#88)
 Changes in 0.22.1
 =================
 - Declare that Py3.5 is not supported in package metadata #2449
 - Moved CI from Travis to Github-Actions
 Changes in 0.22.0
 =================
 - Fix LazyReferenceField dereferencing in embedded documents #2426
 - Fix regarding the recent use of Cursor.__spec in .count() that was interfering with mongomock #2425
 - Drop support for Python 3.5 by introducing f-strings in the codebase
 Changes in 0.21.0
 =================
 - Bug fix in DynamicDocument which is not parsing known fields in constructor like Document do #2412
 - When using pymongo >= 3.7, make use of Collection.count_documents instead of Collection.count
    and Cursor.count that got deprecated in pymongo >= 3.7.
    This should have a negative impact on performance of count see Issue #2219
 - Fix a bug that made the queryset drop the read_preference after clone().
 - Remove Py3.5 from CI as it reached EOL and add Python 3.9
 - Fix some issues related with db_field/field conflict in constructor #2414
 - BREAKING CHANGE: Fix the behavior of Doc.objects.limit(0) which should return all documents (similar to mongodb) #2311
 - Bug fix in ListField when updating the first item, it was saving the whole list, instead of
    just replacing the first item (as usually done when updating 1 item of the list) #2392
 - Add EnumField: ``mongoengine.fields.EnumField``
 - Refactoring - Remove useless code related to Document.__only_fields and Queryset.only_fields
 - Fix query transformation regarding special operators #2365
 - Bug Fix: Document.save() fails when shard_key is not _id #2154
 Changes in 0.20.0
 =================
 - ATTENTION: Drop support for Python2
 - Add Mongo 4.0 to Travis
 - Fix error when setting a string as a ComplexDateTimeField #2253
 - Bump development Status classifier to Production/Stable #2232
 - Improve Queryset.get to avoid confusing MultipleObjectsReturned message in case multiple match are found #630
 - Fixed a bug causing inaccurate query results, while combining ``__raw__`` and regular filters for the same field #2264
 - Add support for the `elemMatch` projection operator in .fields() (e.g BlogPost.objects.fields(elemMatch__comments="test")) #2267
 - DictField validate failed without default connection (bug introduced in 0.19.0) #2239
 - Remove methods that were deprecated years ago:
    - name parameter in Field constructor e.g `StringField(name="...")`, was replaced by db_field
    - Queryset.slave_okay() was deprecated since pymongo3
    - dropDups was dropped with MongoDB3
    - ``Queryset._ensure_indexes`` and ``Queryset.ensure_indexes``, the right method to use is ``Document.ensure_indexes``
 - Added pre-commit for development/CI #2212
 - Renamed requirements-lint.txt to requirements-dev.txt #2212
 - Support for setting ReadConcern #2255
 Changes in 0.19.1
 =================
 - Tests require Pillow < 7.0.0 as it dropped Python2 support
 - DEPRECATION: The interface of ``QuerySet.aggregate`` method was changed, it no longer takes an unpacked list of
    pipeline steps (*pipeline) but simply takes the pipeline list just like ``pymongo.Collection.aggregate`` does. #2079
 Changes in 0.19.0
 =================
 - BREAKING CHANGE: ``class_check`` and ``read_preference`` keyword arguments are no longer available when filtering a ``QuerySet``. #2112
    - Instead of ``Doc.objects(foo=bar, read_preference=...)`` use ``Doc.objects(foo=bar).read_preference(...)``.
    - Instead of ``Doc.objects(foo=bar, class_check=False)`` use ``Doc.objects(foo=bar).clear_cls_query(...)``.
    - This change also renames the private ``QuerySet._initial_query`` attribute to ``_cls_query``.
 - BREAKING CHANGE: Removed the deprecated ``format`` param from ``QuerySet.explain``. #2113
 - BREAKING CHANGE: Renamed ``MongoEngineConnectionError`` to ``ConnectionFailure``. #2111
    - If you catch/use ``MongoEngineConnectionError`` in your code, you'll have to rename it.
 - BREAKING CHANGE: Positional arguments when instantiating a document are no longer supported. #2103
    - From now on keyword arguments (e.g. ``Doc(field_name=value)``) are required.
 - BREAKING CHANGE: A ``LazyReferenceField`` is now stored in the ``_data`` field of its parent as a ``DBRef``, ``Document``, or ``EmbeddedDocument`` (``ObjectId`` is no longer allowed). #2182
 - DEPRECATION: ``Q.empty`` & ``QNode.empty`` are marked as deprecated and will be removed in a next version of MongoEngine. #2210
    - Added ability to check if Q or QNode are empty by parsing them to bool.
    - Instead of ``Q(name="John").empty`` use ``not Q(name="John")``.
 - Fix updating/modifying/deleting/reloading a document that's sharded by a field with ``db_field`` specified. #2125
 - Only set no_cursor_timeout when requested (fixes an incompatibility with MongoDB 4.2) #2148
 - ``ListField`` now accepts an optional ``max_length`` parameter. #2110
 - Improve error message related to InvalidDocumentError #2180
 - Added BulkWriteError to replace NotUniqueError which was misleading in bulk write insert #2152
 - Added ability to compare Q and Q operations #2204
 - Added ability to use a db alias on query_counter #2194
 - Added ability to specify collations for querysets with ``Doc.objects.collation`` #2024
 - Fix updates of a list field by negative index #2094
 - Switch from nosetest to pytest as test runner #2114
 - The codebase is now formatted using ``black``. #2109
 - Documentation improvements:
    - Documented how `pymongo.monitoring` can be used to log all queries issued by MongoEngine to the driver.
 Changes in 0.18.2
 =================
 - Replace deprecated PyMongo v2.x methods with their v3.x equivalents in the ``SequenceField``. #2097
 - Various code clarity and documentation improvements.
 Changes in 0.18.1
 =================
 - Fix a bug introduced in 0.18.0 which was causing ``Document.save`` to update all the fields instead of updating only the modified fields. This bug only occurred when using a custom PK. #2082
 - Add Python 3.7 to Travis CI. #2058
 Changes in 0.18.0
 =================
 - Drop support for EOL'd MongoDB v2.6, v3.0, and v3.2.
 - MongoEngine now requires PyMongo >= v3.4. Travis CI now tests against MongoDB v3.4 – v3.6 and PyMongo v3.4 – v3.6. #2017 #2066
 - Improve performance by avoiding a call to ``to_mongo`` in ``Document.save``. #2049
 - Connection/disconnection improvements:
    - Expose ``mongoengine.connection.disconnect`` and ``mongoengine.connection.disconnect_all``.
    - Fix disconnecting. #566 #1599 #605 #607 #1213 #565
    - Improve documentation of ``connect``/``disconnect``.
    - Fix issue when using multiple connections to the same mongo with different credentials. #2047
    - ``connect`` fails immediately when db name contains invalid characters. #2031 #1718
 - Fix the default write concern of ``Document.save`` that was overwriting the connection write concern. #568
 - Fix querying on ``List(EmbeddedDocument)`` subclasses fields. #1961 #1492
 - Fix querying on ``(Generic)EmbeddedDocument`` subclasses fields. #475
 - Fix ``QuerySet.aggregate`` so that it takes limit and skip value into account. #2029
 - Generate unique indices for ``SortedListField`` and ``EmbeddedDocumentListFields``. #2020
 - BREAKING CHANGE: Changed the behavior of a custom field validator (i.e ``validation`` parameter of a ``Field``). It is now expected to raise a ``ValidationError`` instead of returning ``True``/``False``. #2050
 - BREAKING CHANGES (associated with connection/disconnection fixes):
    - Calling ``connect`` 2 times with the same alias and different parameter will raise an error (should call ``disconnect`` first).
    - ``disconnect`` now clears ``mongoengine.connection._connection_settings``.
    - ``disconnect`` now clears the cached attribute ``Document._collection``.
 - BREAKING CHANGE: ``EmbeddedDocument.save`` & ``.reload`` no longer exist. #1552
 Changes in 0.17.0
 =================
 - POTENTIAL BREAKING CHANGE: All result fields are now passed, including internal fields (``_cls``, ``_id``) when using ``QuerySet.as_pymongo``. #1976
 - Document a BREAKING CHANGE introduced in 0.15.3 and not reported at that time. #1995
 - DEPRECATION: ``EmbeddedDocument.save`` & ``.reload`` are marked as deprecated and will be removed in a next version of MongoEngine. #1552
 - Fix ``QuerySet.only`` working improperly after using ``QuerySet.count`` of the same instance of a ``QuerySet``.
 - Fix ``batch_size`` that was not copied when cloning a ``QuerySet`` object. #2011
 - Fix ``InvalidStringData`` error when using ``modify`` on a ``BinaryField``. #1127
 - Fix test suite and CI to support MongoDB v3.4. #1445
 - Fix reference fields querying the database on each access if value contains orphan DBRefs.
 Changes in 0.16.3
 =================
 - Fix ``$push`` with the ``$position`` operator not working with lists in embedded documents. #1965
 Changes in 0.16.2
 =================
 - Fix ``Document.save`` that fails when called with ``write_concern=None`` (regression of 0.16.1). #1958
 Changes in 0.16.1
 =================
 - Fix ``_cls`` that is not set properly in the ``Document`` constructor (regression). #1950
 - Fix a bug in the ``_delta`` method - update of a ``ListField`` depends on an unrelated dynamic field update. #1733
 - Remove PyMongo's deprecated ``Collection.save`` method and use ``Collection.insert_one`` instead. #1899
 Changes in 0.16.0
 =================
 - POTENTIAL BREAKING CHANGES:
    - ``EmbeddedDocumentField`` will no longer accept references to Document classes in its constructor. #1661
    - Get rid of the ``basecls`` parameter from the ``DictField`` constructor (dead code). #1876
    - Default value of the ``ComplexDateTime`` field is now ``None`` (and no longer the current datetime). #1368
 - Fix an unhashable ``TypeError`` when referencing a ``Document`` with a compound key in an ``EmbeddedDocument``. #1685
 - Fix a bug where an ``EmbeddedDocument`` with the same id as its parent would not be tracked for changes. #1768
 - Fix the fact that a bulk ``QuerySet.insert`` was not setting primary keys of inserted document instances. #1919
 - Fix a bug when referencing an abstract class in a ``ReferenceField``. #1920
 - Allow modifications to the document made in ``pre_save_post_validation`` to be taken into account. #1202
 - Replace MongoDB v2.4 tests in Travis CI with MongoDB v3.2. #1903
 - Fix side effects of using ``QuerySet.no_dereference`` on other documents. #1677
 - Fix ``TypeError`` when using lazy Django translation objects as translated choices. #1879
 - Improve Python 2-3 codebase compatibility. #1889
 - Fix support for changing the default value of the ``ComplexDateTime`` field. #1368
 - Improve error message in case an ``EmbeddedDocumentListField`` receives an ``EmbeddedDocument`` instance instead of a list. #1877
 - Fix the ``inc`` and ``dec`` operators for the ``DecimalField``. #1517 #1320
 - Ignore ``killcursors`` queries in ``query_counter`` context manager. #1869
 - Fix the fact that ``query_counter`` was modifying the initial profiling level in case it was != 0. #1870
 - Repair the ``no_sub_classes`` context manager + fix the fact that it was swallowing exceptions. #1865
 - Fix index creation error that was swallowed by ``hasattr`` under Python 2. #1688
 - ``QuerySet.limit`` function behaviour: Passing 0 as parameter will return all the documents in the cursor. #1611
 - Bulk insert updates the IDs of the input documents instances. #1919
 - Fix a harmless bug related to ``GenericReferenceField`` where modifications in the generic-referenced document were tracked in the parent. #1934
 - Improve validation of the ``BinaryField``. #273
 - Implement lazy regex compiling in Field classes to improve ``import mongoengine`` performance. #1806
 - Update ``GridFSProxy.__str__``  so that it would always print both the filename and grid_id. #710
 - Add ``__repr__`` to ``Q`` and ``QCombination`` classes. #1843
 - Fix bug in the ``BaseList.__iter__`` operator (was occuring when modifying a BaseList while iterating over it). #1676
 - Add a ``DateField``. #513
 - Various improvements to the documentation.
 - Various code quality improvements.
 Changes in 0.15.3
 =================
 - ``Queryset.update/update_one`` methods now return an ``UpdateResult`` when ``full_result=True`` is provided and no longer a dict. #1491
 - Improve ``LazyReferenceField`` and ``GenericLazyReferenceField`` with nested fields. #1704
 - Fix the subfield resolve error in ``generic_emdedded_document`` query. #1651 #1652
 - Use each modifier only with ``$position``. #1673 #1675
 - Fix validation errors in the ``GenericEmbeddedDocumentField``. #1067
 - Update cached fields when a ``fields`` argument is given. #1712
 - Add a ``db`` parameter to ``register_connection`` for compatibility with ``connect``.
 - Use PyMongo v3.x's ``insert_one`` and ``insert_many`` in ``Document.insert``. #1491
 - Use PyMongo v3.x's ``update_one`` and ``update_many`` in ``Document.update`` and ``QuerySet.update``. #1491
 - Fix how ``reload(fields)`` affects changed fields. #1371
 - Fix a bug where the read-only access to the database fails when trying to create indexes. #1338
 Changes in 0.15.0
 =================
 - Add ``LazyReferenceField`` and ``GenericLazyReferenceField``. #1230
 Changes in 0.14.1
 =================
 - Remove ``SemiStrictDict`` and start using a regular dict for ``BaseDocument._data``. #1630
 - Add support for the ``$position`` param in the ``$push`` operator. #1566
 - Fix ``DateTimeField`` interpreting an empty string as today. #1533
 - Add a missing ``__ne__`` method to the ``GridFSProxy`` class. #1632
 - Fix ``BaseQuerySet._fields_to_db_fields``. #1553
 Changes in 0.14.0
 =================
 - BREAKING CHANGE: Remove the ``coerce_types`` param from ``QuerySet.as_pymongo``. #1549
 - POTENTIAL BREAKING CHANGE: Make ``EmbeddedDocument`` not hashable by default. #1528
 - Improve code quality. #1531, #1540, #1541, #1547
 Changes in 0.13.0
 =================
 - POTENTIAL BREAKING CHANGE: Added Unicode support to the ``EmailField``, see docs/upgrade.rst for details.
 Changes in 0.12.0
 =================
 - POTENTIAL BREAKING CHANGE: Fix ``limit``/``skip``/``hint``/``batch_size`` chaining. #1476
 - POTENTIAL BREAKING CHANGE: Change a public ``QuerySet.clone_into`` method to a private ``QuerySet._clone_into``. #1476
 - Fix the way ``Document.objects.create`` works with duplicate IDs. #1485
 - Fix connecting to a replica set with PyMongo 2.x. #1436
 - Fix using sets in field choices. #1481
 - Fix deleting items from a ``ListField``. #1318
 - Fix an obscure error message when filtering by ``field__in=non_iterable``. #1237
 - Fix behavior of a ``dec`` update operator. #1450
 - Add a ``rename`` update operator. #1454
 - Add validation for the ``db_field`` parameter. #1448
 - Fix the error message displayed when querying an ``EmbeddedDocumentField`` by an invalid value. #1440
 - Fix the error message displayed when validating Unicode URLs. #1486
 - Raise an error when trying to save an abstract document. #1449
 Changes in 0.11.0
 =================
 - BREAKING CHANGE: Rename ``ConnectionError`` to ``MongoEngineConnectionError`` since the former is a built-in exception name in Python v3.x. #1428
 - BREAKING CHANGE: Drop Python v2.6 support. #1428
 - BREAKING CHANGE: ``from mongoengine.base import ErrorClass`` won't work anymore for any error from ``mongoengine.errors`` (e.g. ``ValidationError``). Use ``from mongoengine.errors import ErrorClass instead``. #1428
 - BREAKING CHANGE: Accessing a broken reference will raise a ``DoesNotExist`` error. In the past it used to return ``None``. #1334
 - Fix absent rounding for the ``DecimalField`` when ``force_string`` is set. #1103
 Changes in 0.10.8
 =================
 - Add support for ``QuerySet.batch_size``. (#1426)
 - Fix a query set iteration within an iteration. #1427
 - Fix an issue where specifying a MongoDB URI host would override more information than it should. #1421
 - Add an ability to filter the ``GenericReferenceField`` by an ``ObjectId`` and a ``DBRef``. #1425
 - Fix cascading deletes for models with a custom primary key field. #1247
 - Add ability to specify an authentication mechanism (e.g. X.509). #1333
 - Add support for falsy primary keys (e.g. ``doc.pk = 0``). #1354
 - Fix ``QuerySet.sum/average`` for fields w/ an explicit ``db_field``. #1417
 - Fix filtering by ``embedded_doc=None``. #1422
 - Add support for ``Cursor.comment``. #1420
 - Fix ``doc.get_<field>_display`` methods. #1419
 - Fix the ``__repr__`` method of the ``StrictDict`` #1424
 - Add a deprecation warning for Python v2.6.
 Changes in 0.10.7
 =================
 - Drop Python 3.2 support #1390
 - Fix a bug where a dynamic doc has an index inside a dict field. #1278
 - Fix: ``ListField`` minus index assignment does not work. #1128
 - Fix cascade delete mixing among collections. #1224
 - Add ``signal_kwargs`` argument to ``Document.save``, ``Document.delete`` and ``BaseQuerySet.insert`` to be passed to signals calls. #1206
 - Raise ``OperationError`` when trying to do a ``drop_collection`` on document with no collection set.
 - Fix a bug where a count on ``ListField`` of ``EmbeddedDocumentField`` fails. #1187
 - Fix ``LongField`` values stored as int32 in Python 3. #1253
 - ``MapField`` now handles unicode keys correctly. #1267
 - ``ListField`` now handles negative indicies correctly. #1270
 - Fix an ``AttributeError`` when initializing an ``EmbeddedDocument`` with positional args. #681
 - Fix a ``no_cursor_timeout`` error with PyMongo v3.x. #1304
 - Replace map-reduce based ``QuerySet.sum/average`` with aggregation-based implementations. #1336
 - Fix support for ``__`` to escape field names that match operators' names in ``update``. #1351
 - Fix ``BaseDocument._mark_as_changed``. #1369
 - Add support for pickling ``QuerySet`` instances. #1397
 - Fix connecting to a list of hosts. #1389
 - Fix a bug where accessing broken references wouldn't raise a ``DoesNotExist`` error. #1334
 - Fix not being able to specify ``use_db_field=False`` on ``ListField(EmbeddedDocumentField)`` instances. #1218
 - Improvements to the dictionary field's docs. #1383
 Changes in 0.10.6
 =================
 - Add support for mocking MongoEngine based on mongomock. #1151
 - Fix not being able to run tests on Windows. #1153
 - Allow creation of sparse compound indexes. #1114
 Changes in 0.10.5
 =================
 - Fix for reloading of strict with special fields. #1156
 Changes in 0.10.4
 =================
 - ``SaveConditionError`` is now importable from the top level package. #1165
 - Add a ``QuerySet.upsert_one`` method. #1157
 Changes in 0.10.3
 =================
 - Fix ``read_preference`` (it had chaining issues with PyMongo v2.x and it didn't work at all with PyMongo v3.x). #1042
 Changes in 0.10.2
 =================
 - Allow shard key to point to a field in an embedded document. #551
 - Allow arbirary metadata in fields. #1129
 - ReferenceFields now support abstract document types. #837
 Changes in 0.10.1
 =================
 - Fix infinite recursion with cascade delete rules under specific conditions. #1046
 - Fix ``CachedReferenceField`` bug when loading cached docs as ``DBRef`` but failing to save them. #1047
 - Fix ignored chained options. #842
 - ``Document.save``'s ``save_condition`` error raises a ``SaveConditionError`` exception. #1070
 - Fix ``Document.reload`` for the ``DynamicDocument``. #1050
 - ``StrictDict`` & ``SemiStrictDict`` are shadowed at init time. #1105
 - Fix ``ListField`` negative index assignment not working. #1119
 - Remove code that marks a field as changed when the field has a default value but does not exist in the database. #1126
 - Remove test dependencies (nose and rednose) from install dependencies. #1079
 - Recursively build a query when using the ``elemMatch`` operator. #1130
 - Fix instance back references for lists of embedded documents. #1131
 Changes in 0.10.0
 =================
 - Django support was removed and will be available as a separate extension. #958
 - Allow to load undeclared field with meta attribute 'strict': False #957
 - Support for PyMongo 3+ #946
 - Removed get_or_create() deprecated since 0.8.0. #300
 - Improve Document._created status when switch collection and db #1020
 - Queryset update doesn't go through field validation #453
 - Added support for specifying authentication source as option ``authSource`` in URI. #967
 - Fixed mark_as_changed to handle higher/lower level fields changed. #927
 - ListField of embedded docs doesn't set the _instance attribute when iterating over it #914
 - Support += and *= for ListField #595
 - Use sets for populating dbrefs to dereference
 - Fixed unpickled documents replacing the global field's list. #888
 - Fixed storage of microseconds in ComplexDateTimeField and unused separator option. #910
 - Don't send a "cls" option to ensureIndex (related to https://jira.mongodb.org/browse/SERVER-769)
 - Fix for updating sorting in SortedListField. #978
 - Added __ support to escape field name in fields lookup keywords that match operators names #949
 - Fix for issue where FileField deletion did not free space in GridFS.
 - No_dereference() not respected on embedded docs containing reference. #517
 - Document save raise an exception if save_condition fails #1005
 - Fixes some internal _id handling issue. #961
 - Updated URL and Email Field regex validators, added schemes argument to URLField validation. #652
 - Capped collection multiple of 256. #1011
 - Added ``BaseQuerySet.aggregate_sum`` and ``BaseQuerySet.aggregate_average`` methods.
 - Fix for delete with write_concern {'w': 0}. #1008
 - Allow dynamic lookup for more than two parts. #882
 - Added support for min_distance on geo queries. #831
 - Allow to add custom metadata to fields #705
 Changes in 0.9.0
 ================
 - Update FileField when creating a new file #714
 - Added ``EmbeddedDocumentListField`` for Lists of Embedded Documents. #826
 - ComplexDateTimeField should fall back to None when null=True #864
 - Request Support for $min, $max Field update operators #863
 - ``BaseDict`` does not follow ``setdefault`` #866
 - Add support for $type operator # 766
 - Fix tests for pymongo 2.8+ #877
 - No module named 'django.utils.importlib' (Django dev) #872
 - Field Choices Now Accept Subclasses of Documents
 - Ensure Indexes before Each Save #812
 - Generate Unique Indices for Lists of EmbeddedDocuments #358
 - Sparse fields #515
 - write_concern not in params of Collection#remove #801
 - Better BaseDocument equality check when not saved #798
 - OperationError: Shard Keys are immutable. Tried to update id even though the document is not yet saved #771
 - with_limit_and_skip for count should default like in pymongo #759
 - Fix storing value of precision attribute in DecimalField #787
 - Set attribute to None does not work (at least for fields with default values) #734
 - Querying by a field defined in a subclass raises InvalidQueryError #744
 - Add Support For MongoDB 2.6.X's maxTimeMS #778
 - abstract shouldn't be inherited in EmbeddedDocument # 789
 - Allow specifying the '_cls' as a field for indexes #397
 - Stop ensure_indexes running on a secondaries unless connection is through mongos #746
 - Not overriding default values when loading a subset of fields #399
 - Saving document doesn't create new fields in existing collection #620
 - Added ``Queryset.aggregate`` wrapper to aggregation framework #703
 - Added support to show original model fields on to_json calls instead of db_field #697
 - Added Queryset.search_text to Text indexes searchs #700
 - Fixed tests for Django 1.7 #696
 - Follow ReferenceFields in EmbeddedDocuments with select_related #690
 - Added preliminary support for text indexes #680
 - Added ``elemMatch`` operator as well - ``match`` is too obscure #653
 - Added support for progressive JPEG #486 #548
 - Allow strings to be used in index creation #675
 - Fixed EmbeddedDoc weakref proxy issue #592
 - Fixed nested reference field distinct error #583
 - Fixed change tracking on nested MapFields #539
 - Dynamic fields in embedded documents now visible to queryset.only() / qs.exclude() #425 #507
 - Add authentication_source option to register_connection #178 #464 #573 #580 #590
 - Implemented equality between Documents and DBRefs #597
 - Fixed ReferenceField inside nested ListFields dereferencing problem #368
 - Added the ability to reload specific document fields #100
 - Added db_alias support and fixes for custom map/reduce output #586
 - post_save signal now has access to delta information about field changes #594 #589
 - Don't query with $orderby for qs.get() #600
 - Fix id shard key save issue #636
 - Fixes issue with recursive embedded document errors #557
 - Fix clear_changed_fields() clearing unsaved documents bug #602
 - Removing support for Django 1.4.x, pymongo 2.5.x, pymongo 2.6.x.
 - Removing support for Python < 2.6.6
 - Fixed $maxDistance location for geoJSON $near queries with MongoDB 2.6+ #664
 - QuerySet.modify() and Document.modify() methods to provide find_and_modify() like behaviour #677 #773
 - Added support for the using() method on a queryset #676
 - PYPY support #673
 - Connection pooling #674
 - Avoid to open all documents from cursors in an if stmt #655
 - Ability to clear the ordering #657
 - Raise NotUniqueError in Document.update() on pymongo.errors.DuplicateKeyError #626
 - Slots - memory improvements #625
 - Fixed incorrectly split a query key when it ends with "_" #619
 - Geo docs updates #613
 - Workaround a dateutil bug #608
 - Conditional save for atomic-style operations #511
 - Allow dynamic dictionary-style field access #559
 - Increase email field length to accommodate new TLDs #726
 - index_cls is ignored when deciding to set _cls as index prefix #733
 - Make 'db' argument to connection optional #737
 - Allow atomic update for the entire ``DictField`` #742
 - Added MultiPointField, MultiLineField, MultiPolygonField
 - Fix multiple connections aliases being rewritten #748
 - Fixed a few instances where reverse_delete_rule was written as reverse_delete_rules. #791
 - Make ``in_bulk()`` respect ``no_dereference()`` #775
 - Handle None from model __str__; Fixes #753 #754
 - _get_changed_fields fix for embedded documents with id field. #925
 Changes in 0.8.7
 ================
 - Calling reload on deleted / nonexistent documents raises DoesNotExist (#538)
 - Stop ensure_indexes running on a secondaries (#555)
 - Fix circular import issue with django auth (#531) (#545)
 Changes in 0.8.6
 ================
 - Fix django auth import (#531)
 Changes in 0.8.5
 ================
 - Fix multi level nested fields getting marked as changed (#523)
 - Django 1.6 login fix (#522) (#527)
 - Django 1.6 session fix (#509)
 - EmbeddedDocument._instance is now set when setting the attribute (#506)
 - Fixed EmbeddedDocument with ReferenceField equality issue (#502)
 - Fixed GenericReferenceField serialization order (#499)
 - Fixed count and none bug (#498)
 - Fixed bug with .only() and DictField with digit keys (#496)
 - Added user_permissions to Django User object (#491, #492)
 - Fix updating Geo Location fields (#488)
 - Fix handling invalid dict field value (#485)
 - Added app_label to MongoUser (#484)
 - Use defaults when host and port are passed as None (#483)
 - Fixed distinct casting issue with ListField of EmbeddedDocuments (#470)
 - Fixed Django 1.6 sessions (#454, #480)
 Changes in 0.8.4
 ================
 - Remove database name necessity in uri connection schema (#452)
 - Fixed "$pull" semantics for nested ListFields (#447)
 - Allow fields to be named the same as query operators (#445)
 - Updated field filter logic - can now exclude subclass fields (#443)
 - Fixed dereference issue with embedded listfield referencefields (#439)
 - Fixed slice when using inheritance causing fields to be excluded (#437)
 - Fixed ._get_db() attribute after a Document.switch_db() (#441)
 - Dynamic Fields store and recompose Embedded Documents / Documents correctly (#449)
 - Handle dynamic fieldnames that look like digits (#434)
 - Added get_user_document and improve mongo_auth module (#423)
 - Added str representation of GridFSProxy (#424)
 - Update transform to handle docs erroneously passed to unset (#416)
 - Fixed indexing - turn off _cls (#414)
 - Fixed dereference threading issue in ComplexField.__get__ (#412)
 - Fixed QuerySetNoCache.count() caching (#410)
 - Don't follow references in _get_changed_fields (#422, #417)
 - Allow args and kwargs to be passed through to_json (#420)
 Changes in 0.8.3
 ================
 - Fixed EmbeddedDocuments with ``id`` also storing ``_id`` (#402)
 - Added get_proxy_object helper to filefields (#391)
 - Added QuerySetNoCache and QuerySet.no_cache() for lower memory consumption (#365)
 - Fixed sum and average mapreduce dot notation support (#375, #376, #393)
 - Fixed as_pymongo to return the id (#386)
 - Document.select_related() now respects ``db_alias`` (#377)
 - Reload uses shard_key if applicable (#384)
 - Dynamic fields are ordered based on creation and stored in _fields_ordered (#396)
 - Fixed pickling dynamic documents ``_dynamic_fields`` (#387)
 - Fixed ListField setslice and delslice dirty tracking (#390)
 - Added Django 1.5 PY3 support (#392)
 - Added match ($elemMatch) support for EmbeddedDocuments (#379)
 - Fixed weakref being valid after reload (#374)
 - Fixed queryset.get() respecting no_dereference (#373)
 - Added full_result kwarg to update (#380)
 Changes in 0.8.2
 ================
 - Added compare_indexes helper (#361)
 - Fixed cascading saves which weren't turned off as planned (#291)
 - Fixed Datastructures so instances are a Document or EmbeddedDocument (#363)
 - Improved cascading saves write performance (#361)
 - Fixed ambiguity and differing behaviour regarding field defaults (#349)
 - ImageFields now include PIL error messages if invalid error (#353)
 - Added lock when calling doc.Delete() for when signals have no sender (#350)
 - Reload forces read preference to be PRIMARY (#355)
 - Querysets are now lest restrictive when querying duplicate fields (#332, #333)
 - FileField now honouring db_alias (#341)
 - Removed customised __set__ change tracking in ComplexBaseField (#344)
 - Removed unused var in _get_changed_fields (#347)
 - Added pre_save_post_validation signal (#345)
 - DateTimeField now auto converts valid datetime isostrings into dates (#343)
 - DateTimeField now uses dateutil for parsing if available (#343)
 - Fixed Doc.objects(read_preference=X) not setting read preference (#352)
 - Django session ttl index expiry fixed (#329)
 - Fixed pickle.loads (#342)
 - Documentation fixes
 Changes in 0.8.1
 ================
 - Fixed Python 2.6 django auth importlib issue (#326)
 - Fixed pickle unsaved document regression (#327)
 Changes in 0.8.0
 ================
 - Fixed querying ReferenceField custom_id (#317)
 - Fixed pickle issues with collections (#316)
 - Added ``get_next_value`` preview for SequenceFields (#319)
 - Added no_sub_classes context manager and queryset helper (#312)
 - Querysets now utilises a local cache
 - Changed __len__ behaviour in the queryset (#247, #311)
 - Fixed querying string versions of ObjectIds issue with ReferenceField (#307)
 - Added $setOnInsert support for upserts (#308)
 - Upserts now possible with just query parameters (#309)
 - Upserting is the only way to ensure docs are saved correctly (#306)
 - Fixed register_delete_rule inheritance issue
 - Fix cloning of sliced querysets (#303)
 - Fixed update_one write concern (#302)
 - Updated minimum requirement for pymongo to 2.5
 - Add support for new geojson fields, indexes and queries (#299)
 - If values cant be compared mark as changed (#287)
 - Ensure as_pymongo() and to_json honour only() and exclude() (#293)
 - Document serialization uses field order to ensure a strict order is set (#296)
 - DecimalField now stores as float not string (#289)
 - UUIDField now stores as a binary by default (#292)
 - Added Custom User Model for Django 1.5 (#285)
 - Cascading saves now default to off (#291)
 - ReferenceField now store ObjectId's by default rather than DBRef (#290)
 - Added ImageField support for inline replacements (#86)
 - Added SequenceField.set_next_value(value) helper (#159)
 - Updated .only() behaviour - now like exclude it is chainable (#202)
 - Added with_limit_and_skip support to count() (#235)
 - Objects queryset manager now inherited (#256)
 - Updated connection to use MongoClient (#262, #274)
 - Fixed db_alias and inherited Documents (#143)
 - Documentation update for document errors (#124)
 - Deprecated ``get_or_create`` (#35)
 - Updated inheritable objects created by upsert now contain _cls (#118)
 - Added support for creating documents with embedded documents in a single operation (#6)
 - Added to_json and from_json to Document (#1)
 - Added to_json and from_json to QuerySet (#131)
 - Updated index creation now tied to Document class (#102)
 - Added none() to queryset (#127)
 - Updated SequenceFields to allow post processing of the calculated counter value (#141)
 - Added clean method to documents for pre validation data cleaning (#60)
 - Added support setting for read prefrence at a query level (#157)
 - Added _instance to EmbeddedDocuments pointing to the parent (#139)
 - Inheritance is off by default (#122)
 - Remove _types and just use _cls for inheritance (#148)
 - Only allow QNode instances to be passed as query objects (#199)
 - Dynamic fields are now validated on save (#153) (#154)
 - Added support for multiple slices and made slicing chainable. (#170) (#190) (#191)
 - Fixed GridFSProxy __getattr__ behaviour (#196)
 - Fix Django timezone support (#151)
 - Simplified Q objects, removed QueryTreeTransformerVisitor (#98) (#171)
 - FileFields now copyable (#198)
 - Querysets now return clones and are no longer edit in place (#56)
 - Added support for $maxDistance (#179)
 - Uses getlasterror to test created on updated saves (#163)
 - Fixed inheritance and unique index creation (#140)
 - Fixed reverse delete rule with inheritance (#197)
 - Fixed validation for GenericReferences which haven't been dereferenced
 - Added switch_db context manager (#106)
 - Added switch_db method to document instances (#106)
 - Added no_dereference context manager (#82) (#61)
 - Added switch_collection context manager (#220)
 - Added switch_collection method to document instances (#220)
 - Added support for compound primary keys (#149) (#121)
 - Fixed overriding objects with custom manager (#58)
 - Added no_dereference method for querysets (#82) (#61)
 - Undefined data should not override instance methods (#49)
 - Added Django Group and Permission (#142)
 - Added Doc class and pk to Validation messages (#69)
 - Fixed Documents deleted via a queryset don't call any signals (#105)
 - Added the "get_decoded" method to the MongoSession class (#216)
 - Fixed invalid choices error bubbling (#214)
 - Updated Save so it calls $set and $unset in a single operation (#211)
 - Fixed inner queryset looping (#204)
 Changes in 0.7.10
 =================
 - Fix UnicodeEncodeError for dbref (#278)
 - Allow construction using positional parameters (#268)
 - Updated EmailField length to support long domains (#243)
 - Added 64-bit integer support (#251)
 - Added Django sessions TTL support (#224)
 - Fixed issue with numerical keys in MapField(EmbeddedDocumentField()) (#240)
 - Fixed clearing _changed_fields for complex nested embedded documents (#237, #239, #242)
 - Added "id" back to _data dictionary (#255)
 - Only mark a field as changed if the value has changed (#258)
 - Explicitly check for Document instances when dereferencing (#261)
 - Fixed order_by chaining issue (#265)
 - Added dereference support for tuples (#250)
 - Resolve field name to db field name when using distinct(#260, #264, #269)
 - Added kwargs to doc.save to help interop with django (#223, #270)
 - Fixed cloning querysets in PY3
 - Int fields no longer unset in save when changed to 0 (#272)
 - Fixed ReferenceField query chaining bug fixed (#254)
 Changes in 0.7.9
 ================
 - Better fix handling for old style _types
 - Embedded SequenceFields follow collection naming convention
 Changes in 0.7.8
 ================
 - Fix sequence fields in embedded documents (#166)
 - Fix query chaining with .order_by() (#176)
 - Added optional encoding and collection config for Django sessions (#180, #181, #183)
 - Fixed EmailField so can add extra validation (#173, #174, #187)
 - Fixed bulk inserts can now handle custom pk's (#192)
 - Added as_pymongo method to return raw or cast results from pymongo (#193)
 Changes in 0.7.7
 ================
 - Fix handling for old style _types
 Changes in 0.7.6
 ================
 - Unicode fix for repr (#133)
 - Allow updates with match operators (#144)
 - Updated URLField - now can have a override the regex (#136)
 - Allow Django AuthenticationBackends to work with Django user (hmarr/mongoengine#573)
 - Fixed reload issue with ReferenceField where dbref=False (#138)
 Changes in 0.7.5
 ================
 - ReferenceFields with dbref=False use ObjectId instead of strings (#134)
  See ticket for upgrade notes (#134)
 Changes in 0.7.4
 ================
 - Fixed index inheritance issues - firmed up testcases (#123) (#125)
 Changes in 0.7.3
 ================
 - Reverted EmbeddedDocuments meta handling - now can turn off inheritance (#119)
 Changes in 0.7.2
 ================
 - Update index spec generation so its not destructive (#113)
 Changes in 0.7.1
 ================
 - Fixed index spec inheritance (#111)
 Changes in 0.7.0
 ================
 - Updated queryset.delete so you can use with skip / limit (#107)
 - Updated index creation allows kwargs to be passed through refs (#104)
 - Fixed Q object merge edge case (#109)
 - Fixed reloading on sharded documents (hmarr/mongoengine#569)
 - Added NotUniqueError for duplicate keys (#62)
 - Added custom collection / sequence naming for SequenceFields (#92)
 - Fixed UnboundLocalError in composite index with pk field (#88)
 - Updated ReferenceField's to optionally store ObjectId strings
-  this will become the default in 0.8 (#89)
+  this will become the default in 0.8 (MongoEngine/mongoengine#89)
- Added FutureWarning - save will default to ``cascade=False`` in 0.8
+- Added FutureWarning - save will default to `cascade=False` in 0.8
- Added example of indexing embedded document fields (#75)
+- Added example of indexing embedded document fields (MongoEngine/mongoengine#75)
- Fixed ImageField resizing when forcing size (#80)
+- Fixed ImageField resizing when forcing size (MongoEngine/mongoengine#80)
- Add flexibility for fields handling bad data (#78)
+- Add flexibility for fields handling bad data (MongoEngine/mongoengine#78)
 - Embedded Documents no longer handle meta definitions
- Use weakref proxies in base lists / dicts (#74)
+- Use weakref proxies in base lists / dicts (MongoEngine/mongoengine#74)
 - Improved queryset filtering (hmarr/mongoengine#554)
 - Fixed Dynamic Documents and Embedded Documents (hmarr/mongoengine#561)
- Fixed abstract classes and shard keys (#64)
+- Fixed abstract classes and shard keys (MongoEngine/mongoengine#64)
 - Fixed Python 2.5 support
 - Added Python 3 support (thanks to Laine Heron)
 Changes in 0.6.20
 =================
- Added support for distinct and db_alias (#59)
+- Added support for distinct and db_alias (MongoEngine/mongoengine#59)
 - Improved support for chained querysets when constraining the same fields (hmarr/mongoengine#554)
- Fixed BinaryField lookup re (#48)
+- Fixed BinaryField lookup re (MongoEngine/mongoengine#48)
 Changes in 0.6.19
 =================
- Added Binary support to UUID (#47)
+- Added Binary support to UUID (MongoEngine/mongoengine#47)
- Fixed MapField lookup for fields without declared lookups (#46)
+- Fixed MapField lookup for fields without declared lookups (MongoEngine/mongoengine#46)
- Fixed BinaryField python value issue (#48)
+- Fixed BinaryField python value issue (MongoEngine/mongoengine#48)
- Fixed SequenceField non numeric value lookup (#41)
+- Fixed SequenceField non numeric value lookup (MongoEngine/mongoengine#41)
- Fixed queryset manager issue (#52)
+- Fixed queryset manager issue (MongoEngine/mongoengine#52)
 - Fixed FileField comparision (hmarr/mongoengine#547)
 Changes in 0.6.18
@ -762,7 +80,7 @@ Changes in 0.6.12
 - Fixes error with _delta handling DBRefs
 Changes in 0.6.11
-=================
+==================
 - Fixed inconsistency handling None values field attrs
 - Fixed map_field embedded db_field issue
 - Fixed .save() _delta issue with DbRefs
@ -787,7 +105,7 @@ Changes in 0.6.8
 ================
 - Fixed FileField losing reference when no default set
 - Removed possible race condition from FileField (grid_file)
- Added assignment to save, can now do: ``b = MyDoc(**kwargs).save()``
+- Added assignment to save, can now do: `b = MyDoc(**kwargs).save()`
 - Added support for pull operations on nested EmbeddedDocuments
 - Added support for choices with GenericReferenceFields
 - Added support for choices with GenericEmbeddedDocumentFields
@ -802,7 +120,7 @@ Changes in 0.6.7
 - Fixed indexing on '_id' or 'pk' or 'id'
 - Invalid data from the DB now raises a InvalidDocumentError
 - Cleaned up the Validation Error - docs and code
- Added meta ``auto_create_index`` so you can disable index creation
+- Added meta `auto_create_index` so you can disable index creation
 - Added write concern options to inserts
 - Fixed typo in meta for index options
 - Bug fix Read preference now passed correctly
@ -842,7 +160,8 @@ Changes in 0.6.1
 - Fix for replicaSet connections
 Changes in 0.6
-==============
+================
 - Added FutureWarning to inherited classes not declaring 'allow_inheritance' as the default will change in 0.7
 - Added support for covered indexes when inheritance is off
 - No longer always upsert on save for items with a '_id'
@ -929,8 +248,8 @@ Changes in v0.5
 - Updated default collection naming convention
 - Added Document Mixin support
 - Fixed queryet __repr__ mid iteration
- Added hint() support, so can tell Mongo the proper index to use for the query
+- Added hint() support, so cantell Mongo the proper index to use for the query
- Fixed issue with inconsistent setting of _cls breaking inherited referencing
+- Fixed issue with inconsitent setting of _cls breaking inherited referencing
 - Added help_text and verbose_name to fields to help with some form libs
 - Updated item_frequencies to handle embedded document lookups
 - Added delta tracking now only sets / unsets explicitly changed fields
@ -1067,6 +386,7 @@ Changes in v0.1.3
  querying takes place
 - A few minor bugfixes
 Changes in v0.1.2
 =================
 - Query values may be processed before before being used in queries
@ -1075,6 +395,7 @@ Changes in v0.1.2
 - Added ``BooleanField``
 - Added ``Document.reload()`` method
 Changes in v0.1.1
 =================
 - Documents may now use capped collections
--- a/docs/code/tumblelog.py
+++ b/docs/code/tumblelog.py
@ -1,77 +1,66 @@
 from mongoengine import *
-connect("tumblelog")
+connect('tumblelog')
 class Comment(EmbeddedDocument):
    content = StringField()
    name = StringField(max_length=120)
 class User(Document):
    email = StringField(required=True)
    first_name = StringField(max_length=50)
    last_name = StringField(max_length=50)
 class Post(Document):
    title = StringField(max_length=120, required=True)
    author = ReferenceField(User)
    tags = ListField(StringField(max_length=30))
    comments = ListField(EmbeddedDocumentField(Comment))
    # bugfix
    meta = {"allow_inheritance": True}
 class TextPost(Post):
    content = StringField()
 class ImagePost(Post):
    image_path = StringField()
 class LinkPost(Post):
    link_url = StringField()
 Post.drop_collection()
-john = User(email="jdoe@example.com", first_name="John", last_name="Doe")
+john = User(email='jdoe@example.com', first_name='John', last_name='Doe')
 john.save()
-post1 = TextPost(title="Fun with MongoEngine", author=john)
+post1 = TextPost(title='Fun with MongoEngine', author=john)
-post1.content = "Took a look at MongoEngine today, looks pretty cool."
+post1.content = 'Took a look at MongoEngine today, looks pretty cool.'
-post1.tags = ["mongodb", "mongoengine"]
+post1.tags = ['mongodb', 'mongoengine']
 post1.save()
-post2 = LinkPost(title="MongoEngine Documentation", author=john)
+post2 = LinkPost(title='MongoEngine Documentation', author=john)
-post2.link_url = "http://tractiondigital.com/labs/mongoengine/docs"
+post2.link_url = 'http://tractiondigital.com/labs/mongoengine/docs'
-post2.tags = ["mongoengine"]
+post2.tags = ['mongoengine']
 post2.save()
-print("ALL POSTS")
+print 'ALL POSTS'
-print()
+print
 for post in Post.objects:
-    print(post.title)
+    print post.title
-    # print '=' * post.title.count()
+    print '=' * len(post.title)
    print("=" * 20)
    if isinstance(post, TextPost):
-        print(post.content)
+        print post.content
    if isinstance(post, LinkPost):
-        print("Link:", post.link_url)
+        print 'Link:', post.link_url
-    print()
+    print
-print()
+print
-print("POSTS TAGGED 'MONGODB'")
+print 'POSTS TAGGED \'MONGODB\''
-print()
+print
-for post in Post.objects(tags="mongodb"):
+for post in Post.objects(tags='mongodb'):
-    print(post.title)
+    print post.title
-print()
+print
-num_posts = Post.objects(tags="mongodb").count()
+num_posts = Post.objects(tags='mongodb').count()
-print('Found %d posts with tag "mongodb"' % num_posts)
+print 'Found %d posts with tag "mongodb"' % num_posts
--- a/docs/conf.py
+++ b/docs/conf.py
@ -1,3 +1,4 @@
 # -*- coding: utf-8 -*-
 #
 # MongoEngine documentation build configuration file, created by
 # sphinx-quickstart on Sun Nov 22 18:14:13 2009.
@ -10,44 +11,40 @@
 # All configuration values have a default; values that are commented out
 # serve to show the default.
-import os
+import sys, os
 import sys
 import sphinx_rtd_theme
 import mongoengine
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
-sys.path.insert(0, os.path.abspath(".."))
+sys.path.append(os.path.abspath('..'))
 # -- General configuration -----------------------------------------------------
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
-extensions = ["sphinx.ext.autodoc", "sphinx.ext.todo", "readthedocs_ext.readthedocs"]
+extensions = ['sphinx.ext.autodoc', 'sphinx.ext.todo']
 # Add any paths that contain templates here, relative to this directory.
-templates_path = ["_templates"]
+templates_path = ['_templates']
 # The suffix of source filenames.
-source_suffix = ".rst"
+source_suffix = '.rst'
 # The encoding of source files.
-# source_encoding = 'utf-8'
+#source_encoding = 'utf-8'
 # The master toctree document.
-master_doc = "index"
+master_doc = 'index'
 # General information about the project.
-project = "MongoEngine"
+project = u'MongoEngine'
-copyright = "2009, MongoEngine Authors"  # noqa: A001
+copyright = u'2009-2012, MongoEngine Authors'
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 #
 import mongoengine
 # The short X.Y version.
 version = mongoengine.get_version()
 # The full version, including alpha/beta/rc tags.
@ -55,149 +52,144 @@ release = mongoengine.get_version()
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
-# language = None
+#language = None
 # There are two options for replacing |today|: either, you set today to some
 # non-false value, then it is used:
-# today = ''
+#today = ''
 # Else, today_fmt is used as the format for a strftime call.
-# today_fmt = '%B %d, %Y'
+#today_fmt = '%B %d, %Y'
 # List of documents that shouldn't be included in the build.
-# unused_docs = []
+#unused_docs = []
 # List of directories, relative to source directory, that shouldn't be searched
 # for source files.
-exclude_trees = ["_build"]
+exclude_trees = ['_build']
 # The reST default role (used for this markup: `text`) to use for all documents.
-# default_role = None
+#default_role = None
 # If true, '()' will be appended to :func: etc. cross-reference text.
-# add_function_parentheses = True
+#add_function_parentheses = True
 # If true, the current module name will be prepended to all description
 # unit titles (such as .. function::).
-# add_module_names = True
+#add_module_names = True
 # If true, sectionauthor and moduleauthor directives will be shown in the
 # output. They are ignored by default.
-# show_authors = False
+#show_authors = False
 # The name of the Pygments (syntax highlighting) style to use.
-pygments_style = "sphinx"
+pygments_style = 'sphinx'
 # A list of ignored prefixes for module index sorting.
-# modindex_common_prefix = []
+#modindex_common_prefix = []
 # -- Options for HTML output ---------------------------------------------------
 # The theme to use for HTML and HTML Help pages.  Major themes that come with
 # Sphinx are currently 'default' and 'sphinxdoc'.
-html_theme = "sphinx_rtd_theme"
+html_theme = 'nature'
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
 # documentation.
-html_theme_options = {"canonical_url": "http://docs.mongoengine.org/en/latest/"}
+#html_theme_options = {}
 # Add any paths that contain custom themes here, relative to this directory.
-html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
+html_theme_path = ['_themes']
 # The name for this set of Sphinx documents.  If None, it defaults to
 # "<project> v<release> documentation".
-# html_title = None
+#html_title = None
 # A shorter title for the navigation bar.  Default is the same as html_title.
-# html_short_title = None
+#html_short_title = None
 # The name of an image file (relative to this directory) to place at the top
 # of the sidebar.
-# html_logo = None
+#html_logo = None
 # The name of an image file (within the static path) to use as favicon of the
 # docs.  This file should be a Windows icon file (.ico) being 16x16 or 32x32
 # pixels large.
-html_favicon = "favicon.ico"
+#html_favicon = None
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
-# html_static_path = ['_static']
+#html_static_path = ['_static']
 # If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
 # using the given strftime format.
-# html_last_updated_fmt = '%b %d, %Y'
+#html_last_updated_fmt = '%b %d, %Y'
 # If true, SmartyPants will be used to convert quotes and dashes to
 # typographically correct entities.
 html_use_smartypants = True
 # Custom sidebar templates, maps document names to template names.
-html_sidebars = {
+#html_sidebars = {}
    "index": ["globaltoc.html", "searchbox.html"],
    "**": ["localtoc.html", "relations.html", "searchbox.html"],
 }
 # Additional templates that should be rendered to pages, maps page names to
 # template names.
-# html_additional_pages = {}
+#html_additional_pages = {}
 # If false, no module index is generated.
-# html_use_modindex = True
+#html_use_modindex = True
 # If false, no index is generated.
-# html_use_index = True
+#html_use_index = True
 # If true, the index is split into individual pages for each letter.
-# html_split_index = False
+#html_split_index = False
 # If true, links to the reST sources are added to the pages.
-# html_show_sourcelink = True
+#html_show_sourcelink = True
 # If true, an OpenSearch description file will be output, and all pages will
 # contain a <link> tag referring to it.  The value of this option must be the
 # base URL from which the finished HTML is served.
-# html_use_opensearch = ''
+#html_use_opensearch = ''
 # If nonempty, this is the file name suffix for HTML files (e.g. ".xhtml").
-# html_file_suffix = ''
+#html_file_suffix = ''
 # Output file base name for HTML help builder.
-htmlhelp_basename = "MongoEnginedoc"
+htmlhelp_basename = 'MongoEnginedoc'
 # -- Options for LaTeX output --------------------------------------------------
 # The paper size ('letter' or 'a4').
-latex_paper_size = "a4"
+latex_paper_size = 'a4'
 # The font size ('10pt', '11pt' or '12pt').
-# latex_font_size = '10pt'
+#latex_font_size = '10pt'
 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title, author, documentclass [howto/manual]).
 latex_documents = [
-    ("index", "MongoEngine.tex", "MongoEngine Documentation", "Ross Lawley", "manual")
+  ('index', 'MongoEngine.tex', u'MongoEngine Documentation',
   u'Harry Marr', 'manual'),
 ]
 # The name of an image file (relative to this directory) to place at the top of
 # the title page.
-# latex_logo = None
+#latex_logo = None
 # For "manual" documents, if this is true, then toplevel headings are parts,
 # not chapters.
-# latex_use_parts = False
+#latex_use_parts = False
 # Additional stuff for the LaTeX preamble.
-# latex_preamble = ''
+#latex_preamble = ''
 # Documents to append as an appendix to all manuals.
-# latex_appendices = []
+#latex_appendices = []
 # If false, no module index is generated.
-# latex_use_modindex = True
+#latex_use_modindex = True
 autoclass_content = "both"
--- a/docs/django.rst
+++ b/docs/django.rst
@ -1,19 +1,90 @@
 =============================
 Using MongoEngine with Django
 =============================
 .. note :: Updated to support Django 1.4
 Connecting
 ==========
 In your **settings.py** file, ignore the standard database settings (unless you
 also plan to use the ORM in your project), and instead call
 :func:`~mongoengine.connect` somewhere in the settings module.
 Authentication
 ==============
-Django Support
+MongoEngine includes a Django authentication backend, which uses MongoDB. The
-==============
+:class:`~mongoengine.django.auth.User` model is a MongoEngine
 :class:`~mongoengine.Document`, but implements most of the methods and
 attributes that the standard Django :class:`User` model does - so the two are
 moderately compatible. Using this backend will allow you to store users in
 MongoDB but still use many of the Django authentication infrastucture (such as
 the :func:`login_required` decorator and the :func:`authenticate` function). To
 enable the MongoEngine auth backend, add the following to you **settings.py**
 file::
-.. note:: Django support has been split from the main MongoEngine
+    AUTHENTICATION_BACKENDS = (
-    repository. The *legacy* Django extension may be found bundled with the
+        'mongoengine.django.auth.MongoEngineBackend',
-    0.9 release of MongoEngine.
+    )
 The :mod:`~mongoengine.django.auth` module also contains a
 :func:`~mongoengine.django.auth.get_user` helper function, that takes a user's
 :attr:`id` and returns a :class:`~mongoengine.django.auth.User` object.
 .. versionadded:: 0.1.3
-Help Wanted!
+Sessions
------------
+========
 Django allows the use of different backend stores for its sessions. MongoEngine
 provides a MongoDB-based session backend for Django, which allows you to use
 sessions in you Django application with just MongoDB. To enable the MongoEngine
 session backend, ensure that your settings module has
 ``'django.contrib.sessions.middleware.SessionMiddleware'`` in the
 ``MIDDLEWARE_CLASSES`` field  and ``'django.contrib.sessions'`` in your
 ``INSTALLED_APPS``. From there, all you need to do is add the following line
 into you settings module::
-The MongoEngine team is looking for help contributing and maintaining a new
+    SESSION_ENGINE = 'mongoengine.django.sessions'
-Django extension for MongoEngine! If you have Django experience and would like
+
-to help contribute to the project, please get in touch on the
+.. versionadded:: 0.2.1
-`mailing list <http://groups.google.com/group/mongoengine-users>`_ or by
+
-simply contributing on
+Storage
-`GitHub <https://github.com/MongoEngine/django-mongoengine>`_.
+=======
 With MongoEngine's support for GridFS via the :class:`~mongoengine.FileField`,
 it is useful to have a Django file storage backend that wraps this. The new
 storage module is called :class:`~mongoengine.django.storage.GridFSStorage`.
 Using it is very similar to using the default FileSystemStorage.::
    from mongoengine.django.storage import GridFSStorage
    fs = GridFSStorage()
    filename = fs.save('hello.txt', 'Hello, World!')
 All of the `Django Storage API methods
 <http://docs.djangoproject.com/en/dev/ref/files/storage/>`_ have been
 implemented except :func:`path`. If the filename provided already exists, an
 underscore and a number (before # the file extension, if one exists) will be
 appended to the filename until the generated filename doesn't exist. The
 :func:`save` method will return the new filename.::
    >>> fs.exists('hello.txt')
    True
    >>> fs.open('hello.txt').read()
    'Hello, World!'
    >>> fs.size('hello.txt')
    13
    >>> fs.url('hello.txt')
    'http://your_media_url/hello.txt'
    >>> fs.open('hello.txt').name
    'hello.txt'
    >>> fs.listdir()
    ([], [u'hello.txt'])
 All files will be saved and retrieved in GridFS via the :class::`FileDocument`
 document, allowing easy access to the files without the GridFSStorage
 backend.::
    >>> from mongoengine.django.storage import FileDocument
    >>> FileDocument.objects()
    [<FileDocument: FileDocument object>]
 .. versionadded:: 0.4
--- a/docs/faq.rst
+++ b/docs/faq.rst
@ -1,12 +0,0 @@
 ==========================
 Frequently Asked Questions
 ==========================
 Does MongoEngine support asynchronous drivers (Motor, TxMongo)?
 ---------------------------------------------------------------
 No, MongoEngine is exclusively based on PyMongo and isn't designed to support other driver.
 If this is a requirement for your project, check the alternative:  `uMongo`_ and `MotorEngine`_.
 .. _uMongo: https://umongo.readthedocs.io/
 .. _MotorEngine: https://motorengine.readthedocs.io/
--- a/docs/guide/connecting.rst
+++ b/docs/guide/connecting.rst
@ -4,206 +4,62 @@
 Connecting to MongoDB
 =====================
-Connections in MongoEngine are registered globally and are identified with aliases.
+To connect to a running instance of :program:`mongod`, use the
-If no ``alias`` is provided during the connection, it will use "default" as alias.
+:func:`~mongoengine.connect` function. The first argument is the name of the
-
+database to connect to. If the database does not exist, it will be created. If
-To connect to a running instance of :program:`mongod`, use the :func:`~mongoengine.connect`
+the database requires authentication, :attr:`username` and :attr:`password`
-function. The first argument is the name of the database to connect to::
+arguments may be provided::
    from mongoengine import connect
-    connect('project1')
+    connect('project1', username='webapp', password='pwd123')
 By default, MongoEngine assumes that the :program:`mongod` instance is running
-on **localhost** on port **27017**.
+on **localhost** on port **27017**. If MongoDB is running elsewhere, you may
 provide :attr:`host` and :attr:`port` arguments to
 :func:`~mongoengine.connect`::
-If MongoDB is running elsewhere, you need to provide details on how to connect. There are two ways of
+    connect('project1', host='192.168.1.35', port=12345)
 doing this. Using a connection string in URI format (**this is the preferred method**) or individual attributes
 provided as keyword arguments.
-Connect with URI string
+Uri style connections are also supported as long as you include the database
-=======================
+name - just supply the uri as the :attr:`host` to
 :func:`~mongoengine.connect`::
-When using a connection string in URI format you should specify the connection details
+    connect('project1', host='mongodb://localhost/database_name')
 as the :attr:`host` to :func:`~mongoengine.connect`. In a web application context for instance, the URI
 is typically read from the config file::
-        connect(host="mongodb://127.0.0.1:27017/my_db")
+ReplicaSets
 ===========
-If the database requires authentication, you can specify it in the
+MongoEngine now supports :func:`~pymongo.replica_set_connection.ReplicaSetConnection`
-URI. As each database can have its own users configured, you need to tell MongoDB
+to use them please use a URI style connection and provide the `replicaSet` name in the
-where to look for the user you are working with, that's what the ``?authSource=admin`` bit
+connection kwargs.
 of the MongoDB connection string is for::
    # Connects to 'my_db' database by authenticating
    # with given credentials against the 'admin' database (by default as authSource isn't provided)
    connect(host="mongodb://my_user:my_password@127.0.0.1:27017/my_db")
    # Equivalent to previous connection but explicitly states that
    # it should use admin as the authentication source database
    connect(host="mongodb://my_user:my_password@hostname:port/my_db?authSource=admin")
    # Connects to 'my_db' database by authenticating
    # with given credentials against that same database
    connect(host="mongodb://my_user:my_password@127.0.0.1:27017/my_db?authSource=my_db")
 The URI string can also be used to configure advanced parameters like ssl, replicaSet, etc. For more
 information or example about URI string, you can refer to the `official doc <https://docs.mongodb.com/manual/reference/connection-string/>`_::
    connect(host="mongodb://my_user:my_password@127.0.0.1:27017/my_db?authSource=admin&ssl=true&replicaSet=globaldb")
 .. note:: URI containing SRV records (e.g "mongodb+srv://server.example.com/") can be used as well
 Connect with keyword attributes
 ===============================
 The second option for specifying the connection details is to provide the information as keyword
 attributes to :func:`~mongoengine.connect`::
    connect('my_db', host='127.0.0.1', port=27017)
 If the database requires authentication, :attr:`username`, :attr:`password`
 and :attr:`authentication_source` arguments should be provided::
    connect('my_db', username='my_user', password='my_password', authentication_source='admin')
 The set of attributes that :func:`~mongoengine.connect` recognizes includes but is not limited to:
 :attr:`host`, :attr:`port`, :attr:`read_preference`, :attr:`username`, :attr:`password`, :attr:`authentication_source`, :attr:`authentication_mechanism`,
 :attr:`replicaset`, :attr:`tls`, etc. Most of the parameters accepted by `pymongo.MongoClient <https://pymongo.readthedocs.io/en/stable/api/pymongo/mongo_client.html#pymongo.mongo_client.MongoClient>`_
 can be used with :func:`~mongoengine.connect` and will simply be forwarded when instantiating the `pymongo.MongoClient`.
 .. note:: Database, username and password from URI string overrides
    corresponding parameters in :func:`~mongoengine.connect`, this should
    obviously be avoided: ::
        connect(
            db='test',
            username='user',
            password='12345',
            host='mongodb://admin:qwerty@localhost/production'
        )
    will establish connection to ``production`` database using ``admin`` username and ``qwerty`` password.
 .. note:: Calling :func:`~mongoengine.connect` without argument will establish
    a connection to the "test" database by default
 Read Preferences
 ================
 As stated above, Read preferences are supported through the connection but also via individual
 queries by passing the read_preference ::
    from pymongo import ReadPreference
    Bar.objects().read_preference(ReadPreference.PRIMARY)
    Bar.objects(read_preference=ReadPreference.PRIMARY)
 Multiple Databases
 ==================
-To use multiple databases you can use :func:`~mongoengine.connect` and provide
+Multiple database support was added in MongoEngine 0.6. To use multiple
-an `alias` name for the connection - if no `alias` is provided then "default"
+databases you can use :func:`~mongoengine.connect` and provide an `alias` name
-is used.
+for the connection - if no `alias` is provided then "default" is used.
 In the background this uses :func:`~mongoengine.register_connection` to
 store the data and you can register all aliases up front if required.
-Documents defined in different database
+Individual documents can also support multiple databases by providing a
---------------------------------------
+`db_alias` in their meta data.  This allows :class:`~pymongo.dbref.DBRef` objects
-Individual documents can be attached to different databases by providing a
+to point across databases and collections.  Below is an example schema, using
-`db_alias` in their meta data. This allows :class:`~pymongo.dbref.DBRef`
+3 different databases to store data::
 objects to point across databases and collections. Below is an example schema,
 using 3 different databases to store data::
        connect(alias='user-db-alias', db='user-db')
        connect(alias='book-db-alias', db='book-db')
        connect(alias='users-books-db-alias', db='users-books-db')
        class User(Document):
            name = StringField()
-            meta = {'db_alias': 'user-db-alias'}
+            meta = {"db_alias": "user-db"}
        class Book(Document):
            name = StringField()
-            meta = {'db_alias': 'book-db-alias'}
+            meta = {"db_alias": "book-db"}
        class AuthorBooks(Document):
            author = ReferenceField(User)
            book = ReferenceField(Book)
-            meta = {'db_alias': 'users-books-db-alias'}
+            meta = {"db_alias": "users-books-db"}
 Disconnecting an existing connection
 ------------------------------------
 The function :func:`~mongoengine.disconnect` can be used to
 disconnect a particular connection. This can be used to change a
 connection globally::
        from mongoengine import connect, disconnect
        connect('a_db', alias='db1')
        class User(Document):
            name = StringField()
            meta = {'db_alias': 'db1'}
        disconnect(alias='db1')
        connect('another_db', alias='db1')
 .. note:: Calling :func:`~mongoengine.disconnect` without argument
    will disconnect the "default" connection
 .. note:: Since connections gets registered globally, it is important
    to use the `disconnect` function from MongoEngine and not the
    `disconnect()` method of an existing connection (pymongo.MongoClient)
 .. note:: :class:`~mongoengine.Document` are caching the pymongo collection.
    using `disconnect` ensures that it gets cleaned as well
 Context Managers
 ================
 Sometimes you may want to switch the database or collection to query against.
 For example, archiving older data into a separate database for performance
 reasons or writing functions that dynamically choose collections to write
 a document to.
 Switch Database
 ---------------
 The :class:`~mongoengine.context_managers.switch_db` context manager allows
 you to change the database alias for a given class allowing quick and easy
 access to the same User document across databases::
    from mongoengine.context_managers import switch_db
    class User(Document):
        name = StringField()
        meta = {'db_alias': 'user-db'}
    with switch_db(User, 'archive-user-db') as User:
        User(name='Ross').save()  # Saves the 'archive-user-db'
 Switch Collection
 -----------------
 The :func:`~mongoengine.context_managers.switch_collection` context manager
 allows you to change the collection for a given class allowing quick and easy
 access to the same Group document across collection::
        from mongoengine.context_managers import switch_collection
        class Group(Document):
            name = StringField()
        Group(name='test').save()  # Saves in the default db
        with switch_collection(Group, 'group2000') as Group:
            Group(name='hello Group 2000 collection!').save()  # Saves in group2000 collection
 .. note:: Make sure any aliases have been registered with
    :func:`~mongoengine.register_connection` or :func:`~mongoengine.connect`
    before using the context manager.
--- a/docs/guide/defining-documents.rst
+++ b/docs/guide/defining-documents.rst
@ -4,7 +4,7 @@ Defining documents
 In MongoDB, a **document** is roughly equivalent to a **row** in an RDBMS. When
 working with relational databases, rows are stored in **tables**, which have a
 strict **schema** that the rows follow. MongoDB stores documents in
-**collections** rather than tables --- the principal difference is that no schema
+**collections** rather than tables - the principle difference is that no schema
 is enforced at a database level.
 Defining a document's schema
@ -22,16 +22,11 @@ objects** as class attributes to the document class::
    class Page(Document):
        title = StringField(max_length=200, required=True)
-        date_modified = DateTimeField(default=datetime.datetime.utcnow)
+        date_modified = DateTimeField(default=datetime.datetime.now)
 As BSON (the binary format for storing data in mongodb) is order dependent,
 documents are serialized based on their field order.
 .. _dynamic-document-schemas:
 Dynamic document schemas
 ========================
-One of the benefits of MongoDB is dynamic schemas for a collection, whilst data
+One of the benefits of MongoDb is dynamic schemas for a collection, whilst data
 should be planned and organised (after all explicit is better than implicit!)
 there are scenarios where having dynamic / expando style documents is desirable.
@ -52,11 +47,10 @@ be saved ::
    >>> Page.objects(tags='mongoengine').count()
    >>> 1
-.. note::
+..note::
   There is one caveat on Dynamic Documents: fields cannot start with `_`
 Dynamic fields are stored in creation order *after* any declared fields.
 Fields
 ======
@ -68,42 +62,31 @@ not provided. Default values may optionally be a callable, which will be called
 to retrieve the value (such as in the above example). The field types available
 are as follows:
-* :class:`~mongoengine.fields.BinaryField`
+* :class:`~mongoengine.BinaryField`
-* :class:`~mongoengine.fields.BooleanField`
+* :class:`~mongoengine.BooleanField`
-* :class:`~mongoengine.fields.ComplexDateTimeField`
+* :class:`~mongoengine.ComplexDateTimeField`
-* :class:`~mongoengine.fields.DateTimeField`
+* :class:`~mongoengine.DateTimeField`
-* :class:`~mongoengine.fields.DecimalField`
+* :class:`~mongoengine.DecimalField`
-* :class:`~mongoengine.fields.DictField`
+* :class:`~mongoengine.DictField`
-* :class:`~mongoengine.fields.DynamicField`
+* :class:`~mongoengine.DynamicField`
-* :class:`~mongoengine.fields.EmailField`
+* :class:`~mongoengine.EmailField`
-* :class:`~mongoengine.fields.EmbeddedDocumentField`
+* :class:`~mongoengine.EmbeddedDocumentField`
-* :class:`~mongoengine.fields.EmbeddedDocumentListField`
+* :class:`~mongoengine.FileField`
-* :class:`~mongoengine.fields.EnumField`
+* :class:`~mongoengine.FloatField`
-* :class:`~mongoengine.fields.FileField`
+* :class:`~mongoengine.GenericEmbeddedDocumentField`
-* :class:`~mongoengine.fields.FloatField`
+* :class:`~mongoengine.GenericReferenceField`
-* :class:`~mongoengine.fields.GenericEmbeddedDocumentField`
+* :class:`~mongoengine.GeoPointField`
-* :class:`~mongoengine.fields.GenericReferenceField`
+* :class:`~mongoengine.ImageField`
-* :class:`~mongoengine.fields.GenericLazyReferenceField`
+* :class:`~mongoengine.IntField`
-* :class:`~mongoengine.fields.GeoPointField`
+* :class:`~mongoengine.ListField`
-* :class:`~mongoengine.fields.ImageField`
+* :class:`~mongoengine.MapField`
-* :class:`~mongoengine.fields.IntField`
+* :class:`~mongoengine.ObjectIdField`
-* :class:`~mongoengine.fields.ListField`
+* :class:`~mongoengine.ReferenceField`
-* :class:`~mongoengine.fields.LongField`
+* :class:`~mongoengine.SequenceField`
-* :class:`~mongoengine.fields.MapField`
+* :class:`~mongoengine.SortedListField`
-* :class:`~mongoengine.fields.ObjectIdField`
+* :class:`~mongoengine.StringField`
-* :class:`~mongoengine.fields.ReferenceField`
+* :class:`~mongoengine.URLField`
-* :class:`~mongoengine.fields.LazyReferenceField`
+* :class:`~mongoengine.UUIDField`
 * :class:`~mongoengine.fields.SequenceField`
 * :class:`~mongoengine.fields.SortedListField`
 * :class:`~mongoengine.fields.StringField`
 * :class:`~mongoengine.fields.URLField`
 * :class:`~mongoengine.fields.UUIDField`
 * :class:`~mongoengine.fields.PointField`
 * :class:`~mongoengine.fields.LineStringField`
 * :class:`~mongoengine.fields.PolygonField`
 * :class:`~mongoengine.fields.MultiPointField`
 * :class:`~mongoengine.fields.MultiLineStringField`
 * :class:`~mongoengine.fields.MultiPolygonField`
 Field arguments
 ---------------
@ -113,6 +96,9 @@ arguments can be set on all fields:
 :attr:`db_field` (Default: None)
    The MongoDB field name.
 :attr:`name` (Default: None)
    The mongoengine field name.
 :attr:`required` (Default: False)
    If set to True and the field is not set on the document instance, a
    :class:`~mongoengine.ValidationError` will be raised when the document is
@ -121,10 +107,10 @@ arguments can be set on all fields:
 :attr:`default` (Default: None)
    A value to use when no value is set for this field.
-    The definition of default parameters follow `the general rules on Python
+    The definion of default parameters follow `the general rules on Python
    <http://docs.python.org/reference/compound_stmts.html#function-definitions>`__,
    which means that some care should be taken when dealing with default mutable objects
-    (like in :class:`~mongoengine.fields.ListField` or :class:`~mongoengine.fields.DictField`)::
+    (like in :class:`~mongoengine.ListField` or :class:`~mongoengine.DictField`)::
        class ExampleFirst(Document):
            # Default an empty list
@ -139,7 +125,6 @@ arguments can be set on all fields:
            # instead to just an object
            values = ListField(IntField(), default=[1,2,3])
    .. note:: Unsetting a field with a default value will revert back to the default.
 :attr:`unique` (Default: False)
    When True, no documents in the collection will have the same value for this
@ -150,16 +135,13 @@ arguments can be set on all fields:
    field, will not have two documents in the collection with the same value.
 :attr:`primary_key` (Default: False)
-    When True, use this field as a primary key for the collection.  `DictField`
+    When True, use this field as a primary key for the collection.
    and `EmbeddedDocuments` both support being the primary key for a document.
    .. note:: If set, this field is also accessible through the `pk` field.
 :attr:`choices` (Default: None)
-    An iterable (e.g. list, tuple or set) of choices to which the value of this
+    An iterable (e.g. a list or tuple) of choices to which the value of this
    field should be limited.
-    Can either be nested tuples of value (stored in mongo) and a
+    Can be either be a nested tuples of value (stored in mongo) and a
    human readable key ::
        SIZE = (('S', 'Small'),
@ -179,33 +161,18 @@ arguments can be set on all fields:
        class Shirt(Document):
            size = StringField(max_length=3, choices=SIZE)
-:attr:`validation` (Optional)
+:attr:`help_text` (Default: None)
-    A callable to validate the value of the field.
+    Optional help text to output with the field - used by form libraries
    The callable takes the value as parameter and should raise a ValidationError
    if validation fails
-    e.g ::
+:attr:`verbose_name` (Default: None)
-
+    Optional human-readable name for the field - used by form libraries
        def _not_empty(val):
            if not val:
                raise ValidationError('value can not be empty')
        class Person(Document):
            name = StringField(validation=_not_empty)
 :attr:`**kwargs` (Optional)
    You can supply additional metadata as arbitrary additional keyword
    arguments.  You can not override existing attributes, however.  Common
    choices include `help_text` and `verbose_name`, commonly used by form and
    widget libraries.
 List fields
 -----------
-MongoDB allows storing lists of items. To add a list of items to a
+MongoDB allows the storage of lists of items. To add a list of items to a
-:class:`~mongoengine.Document`, use the :class:`~mongoengine.fields.ListField` field
+:class:`~mongoengine.Document`, use the :class:`~mongoengine.ListField` field
-type. :class:`~mongoengine.fields.ListField` takes another field object as its first
+type. :class:`~mongoengine.ListField` takes another field object as its first
 argument, which specifies which type elements may be stored within the list::
    class Page(Document):
@ -223,7 +190,7 @@ inherit from :class:`~mongoengine.EmbeddedDocument` rather than
        content = StringField()
 To embed the document within another document, use the
-:class:`~mongoengine.fields.EmbeddedDocumentField` field type, providing the embedded
+:class:`~mongoengine.EmbeddedDocumentField` field type, providing the embedded
 document class as the first argument::
    class Page(Document):
@ -233,22 +200,19 @@ document class as the first argument::
    comment2 = Comment(content='Nice article!')
    page = Page(comments=[comment1, comment2])
 Embedded documents can also leverage the flexibility of :ref:`dynamic-document-schemas:`
 by inheriting :class:`~mongoengine.DynamicEmbeddedDocument`.
 Dictionary Fields
 -----------------
-Often, an embedded document may be used instead of a dictionary – generally
+Often, an embedded document may be used instead of a dictionary -- generally
-embedded documents are recommended as dictionaries don’t support validation
+this is recommended as dictionaries don't support validation or custom field
-or custom field types. However, sometimes you will not know the structure of what you want to
+types. However, sometimes you will not know the structure of what you want to
-store; in this situation a :class:`~mongoengine.fields.DictField` is appropriate::
+store; in this situation a :class:`~mongoengine.DictField` is appropriate::
    class SurveyResponse(Document):
        date = DateTimeField()
        user = ReferenceField(User)
        answers = DictField()
-    survey_response = SurveyResponse(date=datetime.utcnow(), user=request.user)
+    survey_response = SurveyResponse(date=datetime.now(), user=request.user)
    response_form = ResponseForm(request.POST)
    survey_response.answers = response_form.cleaned_data()
    survey_response.save()
@ -259,7 +223,7 @@ other objects, so are the most flexible field type available.
 Reference fields
 ----------------
 References may be stored to other documents in the database using the
-:class:`~mongoengine.fields.ReferenceField`. Pass in another document class as the
+:class:`~mongoengine.ReferenceField`. Pass in another document class as the
 first argument to the constructor, then simply assign document objects to the
 field::
@ -280,9 +244,9 @@ field::
 The :class:`User` object is automatically turned into a reference behind the
 scenes, and dereferenced when the :class:`Page` object is retrieved.
-To add a :class:`~mongoengine.fields.ReferenceField` that references the document
+To add a :class:`~mongoengine.ReferenceField` that references the document
 being defined, use the string ``'self'`` in place of the document class as the
-argument to :class:`~mongoengine.fields.ReferenceField`'s constructor. To reference a
+argument to :class:`~mongoengine.ReferenceField`'s constructor. To reference a
 document that has not yet been defined, use the name of the undefined document
 as the constructor's argument::
@ -295,12 +259,12 @@ as the constructor's argument::
        content = StringField()
-.. _many-to-many-with-listfields:
+.. _one-to-many-with-listfields:
-Many to Many with ListFields
+One to Many with ListFields
 '''''''''''''''''''''''''''
-If you are implementing a many to many relationship via a list of references,
+If you are implementing a one to many relationship via a list of references,
 then the references are stored as DBRefs and to query you need to pass an
 instance of the object to the query::
@ -323,12 +287,6 @@ instance of the object to the query::
    # Find all pages that both Bob and John have authored
    Page.objects(authors__all=[bob, john])
    # Remove Bob from the authors for a page.
    Page.objects(id='...').update_one(pull__authors=bob)
    # Add John to the authors for a page.
    Page.objects(id='...').update_one(push__authors=john)
 Dealing with deletion of referred documents
 '''''''''''''''''''''''''''''''''''''''''''
@ -340,11 +298,12 @@ reference with a delete rule specification.  A delete rule is specified by
 supplying the :attr:`reverse_delete_rule` attributes on the
 :class:`ReferenceField` definition, like this::
-    class ProfilePage(Document):
+    class Employee(Document):
-        employee = ReferenceField('Employee', reverse_delete_rule=mongoengine.CASCADE)
+        ...
        profile_page = ReferenceField('ProfilePage', reverse_delete_rule=mongoengine.NULLIFY)
 The declaration in this example means that when an :class:`Employee` object is
-removed, the :class:`ProfilePage` that references that employee is removed as
+removed, the :class:`ProfilePage` that belongs to that employee is removed as
 well.  If a whole batch of employees is removed, all profile pages that are
 linked are removed as well.
@ -357,15 +316,15 @@ Its value can take any of the following constants:
  Deletion is denied if there still exist references to the object being
  deleted.
 :const:`mongoengine.NULLIFY`
-  Any object's fields still referring to the object being deleted are set to None
+  Any object's fields still referring to the object being deleted are removed
  (using MongoDB's "unset" operation), effectively nullifying the relationship.
 :const:`mongoengine.CASCADE`
-  Any object containing fields that are referring to the object being deleted
+  Any object containing fields that are refererring to the object being deleted
  are deleted first.
 :const:`mongoengine.PULL`
  Removes the reference to the object (using MongoDB's "pull" operation)
  from any object's fields of
-  :class:`~mongoengine.fields.ListField` (:class:`~mongoengine.fields.ReferenceField`).
+  :class:`~mongoengine.ListField` (:class:`~mongoengine.ReferenceField`).
 .. warning::
@ -384,10 +343,11 @@ Its value can take any of the following constants:
   In Django, be sure to put all apps that have such delete rule declarations in
   their :file:`models.py` in the :const:`INSTALLED_APPS` tuple.
 Generic reference fields
 ''''''''''''''''''''''''
 A second kind of reference field also exists,
-:class:`~mongoengine.fields.GenericReferenceField`. This allows you to reference any
+:class:`~mongoengine.GenericReferenceField`. This allows you to reference any
 kind of :class:`~mongoengine.Document`, and hence doesn't take a
 :class:`~mongoengine.Document` subclass as a constructor argument::
@ -411,18 +371,18 @@ kind of :class:`~mongoengine.Document`, and hence doesn't take a
 .. note::
-   Using :class:`~mongoengine.fields.GenericReferenceField`\ s is slightly less
+   Using :class:`~mongoengine.GenericReferenceField`\ s is slightly less
-   efficient than the standard :class:`~mongoengine.fields.ReferenceField`\ s, so if
+   efficient than the standard :class:`~mongoengine.ReferenceField`\ s, so if
   you will only be referencing one document type, prefer the standard
-   :class:`~mongoengine.fields.ReferenceField`.
+   :class:`~mongoengine.ReferenceField`.
 Uniqueness constraints
 ----------------------
 MongoEngine allows you to specify that a field should be unique across a
-collection by providing ``unique=True`` to a :class:`~mongoengine.fields.Field`\ 's
+collection by providing ``unique=True`` to a :class:`~mongoengine.Field`\ 's
 constructor. If you try to save a document that has the same value for a unique
 field as a document that is already in the database, a
-:class:`~mongoengine.NotUniqueError` will be raised. You may also specify
+:class:`~mongoengine.OperationError` will be raised. You may also specify
 multi-field uniqueness constraints by using :attr:`unique_with`, which may be
 either a single field name, or a list or tuple of field names::
@ -431,15 +391,28 @@ either a single field name, or a list or tuple of field names::
        first_name = StringField()
        last_name = StringField(unique_with='first_name')
 Skipping Document validation on save
 ------------------------------------
 You can also skip the whole document validation process by setting
 ``validate=False`` when caling the :meth:`~mongoengine.document.Document.save`
 method::
    class Recipient(Document):
        name = StringField()
        email = EmailField()
    recipient = Recipient(name='admin', email='root@localhost')
    recipient.save()               # will raise a ValidationError while
    recipient.save(validate=False) # won't
 Document collections
 ====================
 Document classes that inherit **directly** from :class:`~mongoengine.Document`
 will have their own **collection** in the database. The name of the collection
-is by default the name of the class converted to snake_case (e.g if your Document class
+is by default the name of the class, coverted to lowercase (so in the example
-is named `CompanyUser`, the corresponding collection would be `company_user`). If you need
+above, the collection would be called `page`). If you need to change the name
-to change the name of the collection (e.g. to use MongoEngine with an existing database),
+of the collection (e.g. to use MongoEngine with an existing database), then
-then create a class dictionary attribute called :attr:`meta` on your document, and
+create a class dictionary attribute called :attr:`meta` on your document, and
 set :attr:`collection` to the name of the collection that you want your
 document class to use::
@ -453,10 +426,8 @@ A :class:`~mongoengine.Document` may use a **Capped Collection** by specifying
 :attr:`max_documents` and :attr:`max_size` in the :attr:`meta` dictionary.
 :attr:`max_documents` is the maximum number of documents that is allowed to be
 stored in the collection, and :attr:`max_size` is the maximum size of the
-collection in bytes. :attr:`max_size` is rounded up to the next multiple of 256
+collection in bytes. If :attr:`max_size` is not specified and
-by MongoDB internally and mongoengine before. Use also a multiple of 256 to
+:attr:`max_documents` is, :attr:`max_size` defaults to 10000000 bytes (10MB).
 avoid confusions. If :attr:`max_size` is not specified and
 :attr:`max_documents` is, :attr:`max_size` defaults to 10485760 bytes (10MB).
 The following example shows a :class:`Log` document that will be limited to
 1000 entries and 2MB of disk space::
@ -464,159 +435,58 @@ The following example shows a :class:`Log` document that will be limited to
        ip_address = StringField()
        meta = {'max_documents': 1000, 'max_size': 2000000}
 .. defining-indexes_
 Indexes
 =======
 You can specify indexes on collections to make querying faster. This is done
 by creating a list of index specifications called :attr:`indexes` in the
 :attr:`~mongoengine.Document.meta` dictionary, where an index specification may
 either be a single field name, a tuple containing multiple field names, or a
-dictionary containing a full index definition.
+dictionary containing a full index definition. A direction may be specified on
-
+fields by prefixing the field name with a **+** or a **-** sign. Note that
-A direction may be specified on fields by prefixing the field name with a
+direction only matters on multi-field indexes. ::
 **+** (for ascending) or a **-** sign (for descending). Note that direction
 only matters on compound indexes. Text indexes may be specified by prefixing
 the field name with a **$**. Hashed indexes may be specified by prefixing
 the field name with a **#**::
    class Page(Document):
        category = IntField()
        title = StringField()
        rating = StringField()
        created = DateTimeField()
        meta = {
-            'indexes': [
+            'indexes': ['title', ('title', '-rating')]
                'title',   # single-field index
                '$title',  # text index
                '#title',  # hashed index
                ('title', '-rating'),  # compound index
                ('category', '_cls'),  # compound index
                {
                    'fields': ['created'],
                    'expireAfterSeconds': 3600  # ttl index
                }
            ]
        }
-If a dictionary is passed then additional options become available. Valid options include,
+If a dictionary is passed then the following options are available:
 but are not limited to:
 :attr:`fields` (Default: None)
    The fields to index. Specified in the same format as described above.
-:attr:`cls` (Default: True)
+:attr:`types` (Default: True)
-    If you have polymorphic models that inherit and have
+    Whether the index should have the :attr:`_types` field added automatically
-    :attr:`allow_inheritance` turned on, you can configure whether the index
+    to the start of the index.
    should have the :attr:`_cls` field added automatically to the start of the
    index.
 :attr:`sparse` (Default: False)
    Whether the index should be sparse.
 :attr:`unique` (Default: False)
-    Whether the index should be unique.
+    Whether the index should be sparse.
-:attr:`expireAfterSeconds` (Optional)
+.. note ::
    Allows you to automatically expire data from a collection by setting the
    time in seconds to expire the a field.
-:attr:`name` (Optional)
+    To index embedded files / dictionary fields use 'dot' notation eg:
-    Allows you to specify a name for the index
+    `rank.title`
-:attr:`collation` (Optional)
+.. warning::
    Allows to create case insensitive indexes (MongoDB v3.4+ only)
-.. note::
+    Inheritance adds extra indices.
    If don't need inheritance for a document turn inheritance off -
    see :ref:`document-inheritance`.
    Additional options are forwarded as **kwargs to pymongo's create_index method.
    Inheritance adds extra fields indices see: :ref:`document-inheritance`.
 Global index default options
 ----------------------------
 There are a few top level defaults for all indexes that can be set::
    class Page(Document):
        title = StringField()
        rating = StringField()
        meta = {
            'index_opts': {},
            'index_background': True,
            'index_cls': False,
            'auto_create_index': True,
        }
 :attr:`index_opts` (Optional)
    Set any default index options - see the `full options list <https://docs.mongodb.com/manual/reference/method/db.collection.createIndex/#db.collection.createIndex>`_
 :attr:`index_background` (Optional)
    Set the default value for if an index should be indexed in the background
 :attr:`index_cls` (Optional)
    A way to turn off a specific index for _cls.
 :attr:`auto_create_index` (Optional)
    When this is True (default), MongoEngine will ensure that the correct
    indexes exist in MongoDB each time a command is run. This can be disabled
    in systems where indexes are managed separately. Disabling this will improve
    performance.
 Compound Indexes and Indexing sub documents
 -------------------------------------------
 Compound indexes can be created by adding the Embedded field or dictionary
 field name to the index definition.
 Sometimes its more efficient to index parts of Embedded / dictionary fields,
 in this case use 'dot' notation to identify the value to index eg: `rank.title`
 .. _geospatial-indexes:
 Geospatial indexes
------------------
+---------------------------
 The best geo index for mongodb is the new "2dsphere", which has an improved
 spherical model and provides better performance and more options when querying.
 The following fields will explicitly add a "2dsphere" index:
    - :class:`~mongoengine.fields.PointField`
    - :class:`~mongoengine.fields.LineStringField`
    - :class:`~mongoengine.fields.PolygonField`
    - :class:`~mongoengine.fields.MultiPointField`
    - :class:`~mongoengine.fields.MultiLineStringField`
    - :class:`~mongoengine.fields.MultiPolygonField`
 As "2dsphere" indexes can be part of a compound index, you may not want the
 automatic index but would prefer a compound index.  In this example we turn off
 auto indexing and explicitly declare a compound index on ``location`` and ``datetime``::
    class Log(Document):
        location = PointField(auto_index=False)
        datetime = DateTimeField()
        meta = {
            'indexes': [[("location", "2dsphere"), ("datetime", 1)]]
        }
 Pre MongoDB 2.4 Geo
 '''''''''''''''''''
 .. note:: For MongoDB < 2.4 this is still current, however the new 2dsphere
    index is a big improvement over the previous 2D model - so upgrading is
    advised.
 Geospatial indexes will be automatically created for all
-:class:`~mongoengine.fields.GeoPointField`\ s
+:class:`~mongoengine.GeoPointField`\ s
 It is also possible to explicitly define geospatial indexes. This is
 useful if you need to define a geospatial index on a subfield of a
-:class:`~mongoengine.fields.DictField` or a custom field that contains a
+:class:`~mongoengine.DictField` or a custom field that contains a
 point. To create a geospatial index you must prefix the field with the
 ***** sign. ::
@ -628,35 +498,6 @@ point. To create a geospatial index you must prefix the field with the
            ],
        }
 Time To Live (TTL) indexes
 --------------------------
 A special index type that allows you to automatically expire data from a
 collection after a given period. See the official
 `ttl <http://docs.mongodb.org/manual/tutorial/expire-data/#expire-data-from-collections-by-setting-ttl>`_
 documentation for more information.  A common usecase might be session data::
    class Session(Document):
        created = DateTimeField(default=datetime.utcnow)
        meta = {
            'indexes': [
                {'fields': ['created'], 'expireAfterSeconds': 3600}
            ]
        }
 .. warning:: TTL indexes happen on the MongoDB server and not in the application
    code, therefore no signals will be fired on document deletion.
    If you need signals to be fired on deletion, then you must handle the
    deletion of Documents in your application code.
 Comparing Indexes
 -----------------
 Use :func:`mongoengine.Document.compare_indexes` to compare actual indexes in
 the database to those that your document definitions define.  This is useful
 for maintenance purposes and ensuring you have the correct indexes for your
 schema.
 Ordering
 ========
 A default ordering can be specified for your
@ -700,17 +541,12 @@ subsequent calls to :meth:`~mongoengine.queryset.QuerySet.order_by`. ::
 Shard keys
 ==========
-If your collection is sharded by multiple keys, then you can improve shard
+If your collection is sharded, then you need to specify the shard key as a tuple,
-routing (and thus the performance of your application) by specifying the shard
+using the :attr:`shard_key` attribute of :attr:`-mongoengine.Document.meta`.
-key, using the :attr:`shard_key` attribute of
+This ensures that the shard key is sent with the query when calling the
-:attr:`~mongoengine.Document.meta`. The shard key should be defined as a tuple.
+:meth:`~mongoengine.document.Document.save` or
-
+:meth:`~mongoengine.document.Document.update` method on an existing
-This ensures that the full shard key is sent with the query when calling
+:class:`-mongoengine.Document` instance::
 methods such as :meth:`~mongoengine.document.Document.save`,
 :meth:`~mongoengine.document.Document.update`,
 :meth:`~mongoengine.document.Document.modify`, or
 :meth:`~mongoengine.document.Document.delete` on an existing
 :class:`~mongoengine.Document` instance::
    class LogEntry(Document):
        machine = StringField()
@ -719,8 +555,7 @@ methods such as :meth:`~mongoengine.document.Document.save`,
        data = StringField()
        meta = {
-            'shard_key': ('machine', 'timestamp'),
+            'shard_key': ('machine', 'timestamp',)
            'indexes': ('machine', 'timestamp'),
        }
 .. _document-inheritance:
@ -730,12 +565,10 @@ Document inheritance
 To create a specialised type of a :class:`~mongoengine.Document` you have
 defined, you may subclass it and add any extra fields or methods you may need.
-As this new class is not a direct subclass of
+As this is new class is not a direct subclass of
 :class:`~mongoengine.Document`, it will not be stored in its own collection; it
 will use the same collection as its superclass uses. This allows for more
-convenient and efficient retrieval of related documents -- all you need do is
+convenient and efficient retrieval of related documents::
 set :attr:`allow_inheritance` to True in the :attr:`meta` data for a
 document.::
    # Stored in a collection named 'page'
    class Page(Document):
@ -747,71 +580,25 @@ document.::
    class DatedPage(Page):
        date = DateTimeField()
-.. note:: From 0.8 onwards :attr:`allow_inheritance` defaults
+.. note:: From 0.7 onwards you must declare `allow_inheritance` in the document meta.
          to False, meaning you must set it to True to use inheritance.
          Setting :attr:`allow_inheritance` to True should also be used in
          :class:`~mongoengine.EmbeddedDocument` class in case you need to subclass it
 When it comes to querying using :attr:`.objects()`, querying `Page.objects()` will query
 both `Page` and `DatedPage` whereas querying `DatedPage` will only query the `DatedPage` documents.
 Behind the scenes, MongoEngine deals with inheritance by adding a :attr:`_cls` attribute that contains
 the class name in every documents. When a document is loaded, MongoEngine checks
 it's :attr:`_cls` attribute and use that class to construct the instance.::
    Page(title='a funky title').save()
    DatedPage(title='another title', date=datetime.utcnow()).save()
    print(Page.objects().count())         # 2
    print(DatedPage.objects().count())    # 1
    # print documents in their native form
    # we remove 'id' to avoid polluting the output with unnecessary detail
    qs = Page.objects.exclude('id').as_pymongo()
    print(list(qs))
    # [
    #   {'_cls': u 'Page', 'title': 'a funky title'},
    #   {'_cls': u 'Page.DatedPage', 'title': u 'another title', 'date': datetime.datetime(2019, 12, 13, 20, 16, 59, 993000)}
    # ]
 Working with existing data
 --------------------------
-As MongoEngine no longer defaults to needing :attr:`_cls`, you can quickly and
+To enable correct retrieval of documents involved in this kind of heirarchy,
-easily get working with existing data.  Just define the document to match
+two extra attributes are stored on each document in the database: :attr:`_cls`
-the expected schema in your database ::
+and :attr:`_types`. These are hidden from the user through the MongoEngine
 interface, but may not be present if you are trying to use MongoEngine with
 an existing database. For this reason, you may disable this inheritance
 mechansim, removing the dependency of :attr:`_cls` and :attr:`_types`, enabling
 you to work with existing databases. To disable inheritance on a document
 class, set :attr:`allow_inheritance` to ``False`` in the :attr:`meta`
 dictionary::
    # Will work with data in an existing collection named 'cmsPage'
    class Page(Document):
        title = StringField(max_length=200, required=True)
        meta = {
-            'collection': 'cmsPage'
+            'collection': 'cmsPage',
            'allow_inheritance': False,
        }
 If you have wildly varying schemas then using a
 :class:`~mongoengine.DynamicDocument` might be more appropriate, instead of
 defining all possible field types.
 If you use :class:`~mongoengine.Document` and the database contains data that
 isn't defined then that data will be stored in the `document._data` dictionary.
 Abstract classes
 ================
 If you want to add some extra functionality to a group of Document classes but
 you don't need or want the overhead of inheritance you can use the
 :attr:`abstract` attribute of :attr:`~mongoengine.Document.meta`.
 This won't turn on :ref:`document-inheritance` but will allow you to keep your
 code DRY::
        class BaseDocument(Document):
            meta = {
                'abstract': True,
            }
            def check_permissions(self):
                ...
        class User(BaseDocument):
           ...
 Now the User class will have access to the inherited `check_permissions` method
 and won't store any of the extra `_cls` information.
--- a/docs/guide/document-instances.rst
+++ b/docs/guide/document-instances.rst
@ -2,7 +2,7 @@
 Documents instances
 ===================
 To create a new document object, create an instance of the relevant document
-class, providing values for its fields as constructor keyword arguments.
+class, providing values for its fields as its constructor keyword arguments.
 You may provide values for any of the fields on the document::
    >>> page = Page(title="Test Page")
@ -30,25 +30,21 @@ already exist, then any changes will be updated atomically.  For example::
 .. note::
-    Changes to documents are tracked and on the whole perform ``set`` operations.
+    Changes to documents are tracked and on the whole perform `set` operations.
-    * ``list_field.push(0)`` --- *sets* the resulting list
+    * ``list_field.pop(0)`` - *sets* the resulting list
-    * ``del(list_field)``   --- *unsets* whole list
+    * ``del(list_field)``   - *unsets* whole list
    With lists its preferable to use ``Doc.update(push__list_field=0)`` as
    this stops the whole list being updated --- stopping any race conditions.
 .. seealso::
    :ref:`guide-atomic-updates`
 Cascading Saves
 ---------------
-If your document contains :class:`~mongoengine.fields.ReferenceField` or
+If your document contains :class:`~mongoengine.ReferenceField` or
-:class:`~mongoengine.fields.GenericReferenceField` objects, then by default the
+:class:`~mongoengine.GenericReferenceField` objects, then by default the
-:meth:`~mongoengine.Document.save` method will not save any changes to
+:meth:`~mongoengine.Document.save` method will automatically save any changes to
-those objects.  If you want all references to be saved also, noting each
+those objects as well.  If this is not desired passing :attr:`cascade` as False
-save is a separate query, then passing :attr:`cascade` as True
+to the save method turns this feature off.
 to the save method will cascade any saves.
 Deleting documents
 ------------------
@ -85,13 +81,12 @@ you may still use :attr:`id` to access the primary key if you want::
    >>> bob.id == bob.email == 'bob@example.com'
    True
-You can also access the document's "primary key" using the :attr:`pk` field,
+You can also access the document's "primary key" using the :attr:`pk` field; in
-it's an alias to :attr:`id`::
+is an alias to :attr:`id`::
    >>> page = Page(title="Another Test Page")
    >>> page.save()
    >>> page.id == page.pk
    True
 .. note::
--- a/docs/guide/gridfs.rst
+++ b/docs/guide/gridfs.rst
@ -2,55 +2,52 @@
 GridFS
 ======
 .. versionadded:: 0.4
 Writing
 -------
-GridFS support comes in the form of the :class:`~mongoengine.fields.FileField` field
+GridFS support comes in the form of the :class:`~mongoengine.FileField` field
 object. This field acts as a file-like object and provides a couple of
 different ways of inserting and retrieving data. Arbitrary metadata such as
-content type can also be stored alongside the files. The object returned when accessing a
+content type can also be stored alongside the files. In the following example,
-FileField is a proxy to `Pymongo's GridFS <https://api.mongodb.com/python/current/examples/gridfs.html#gridfs-example>`_
+a document is created to store details about animals, including a photo::
 In the following example, a document is created to store details about animals, including a photo::
    class Animal(Document):
        genus = StringField()
        family = StringField()
        photo = FileField()
-    marmot = Animal(genus='Marmota', family='Sciuridae')
+    marmot = Animal('Marmota', 'Sciuridae')
    marmot_photo = open('marmot.jpg', 'r')      # Retrieve a photo from disk
    marmot.photo = marmot_photo                 # Store photo in the document
    marmot.photo.content_type = 'image/jpeg'    # Store metadata
    marmot.save()
 Another way of writing to a :class:`~mongoengine.FileField` is to use the
 :func:`put` method. This allows for metadata to be stored in the same call as
 the file::
    marmot.photo.put(marmot_photo, content_type='image/jpeg')
    with open('marmot.jpg', 'rb') as fd:
        marmot.photo.put(fd, content_type = 'image/jpeg')
    marmot.save()
 Retrieval
 ---------
-So using the :class:`~mongoengine.fields.FileField` is just like using any other
+So using the :class:`~mongoengine.FileField` is just like using any other
 field. The file can also be retrieved just as easily::
    marmot = Animal.objects(genus='Marmota').first()
    photo = marmot.photo.read()
    content_type = marmot.photo.content_type
 .. note:: If you need to read() the content of a file multiple times, you'll need to "rewind"
    the file-like object using `seek`::
        marmot = Animal.objects(genus='Marmota').first()
        content1 = marmot.photo.read()
        assert content1 != ""
        content2 = marmot.photo.read()    # will be empty
        assert content2 == ""
        marmot.photo.seek(0)              # rewind the file by setting the current position of the cursor in the file to 0
        content3 = marmot.photo.read()
        assert content3 == content1
 Streaming
 ---------
-Streaming data into a :class:`~mongoengine.fields.FileField` is achieved in a
+Streaming data into a :class:`~mongoengine.FileField` is achieved in a
 slightly different manner.  First, a new file must be created by calling the
 :func:`new_file` method. Data can then be written using :func:`write`::
@ -59,15 +56,14 @@ slightly different manner.  First, a new file must be created by calling the
    marmot.photo.write('some_more_image_data')
    marmot.photo.close()
-    marmot.save()
+    marmot.photo.save()
 Deletion
 --------
 Deleting stored files is achieved with the :func:`delete` method::
-    marmot.photo.delete()    # Deletes the GridFS document
+    marmot.photo.delete()
    marmot.save()            # Saves the GridFS reference (being None) contained in the marmot instance
 .. warning::
@ -84,6 +80,5 @@ Replacing files
 Files can be replaced with the :func:`replace` method. This works just like
 the :func:`put` method so even metadata can (and should) be replaced::
-    another_marmot = open('another_marmot.png', 'rb')
+    another_marmot = open('another_marmot.png', 'r')
-    marmot.photo.replace(another_marmot, content_type='image/png')  # Replaces the GridFS document
+    marmot.photo.replace(another_marmot, content_type='image/png')
    marmot.save()                                                   # Replaces the GridFS reference contained in marmot instance
--- a/docs/guide/index.rst
+++ b/docs/guide/index.rst
@ -10,10 +10,5 @@ User Guide
   defining-documents
   document-instances
   querying
   validation
   gridfs
   signals
   text-indexes
   migration
   logging-monitoring
   mongomock
--- a/docs/guide/installing.rst
+++ b/docs/guide/installing.rst
@ -2,17 +2,17 @@
 Installing MongoEngine
 ======================
-To use MongoEngine, you will need to download `MongoDB <http://mongodb.com/>`_
+To use MongoEngine, you will need to download `MongoDB <http://mongodb.org/>`_
 and ensure it is running in an accessible location. You will also need
 `PyMongo <http://api.mongodb.org/python>`_ to use MongoEngine, but if you
 install MongoEngine using setuptools, then the dependencies will be handled for
 you.
-MongoEngine is available on PyPI, so you can use :program:`pip`:
+MongoEngine is available on PyPI, so to use it you can use :program:`pip`:
 .. code-block:: console
-    $ python -m pip install mongoengine
+    $ pip install mongoengine
 Alternatively, if you don't have setuptools installed, `download it from PyPi
 <http://pypi.python.org/pypi/mongoengine/>`_ and run
@ -22,10 +22,10 @@ Alternatively, if you don't have setuptools installed, `download it from PyPi
    $ python setup.py install
 To use the bleeding-edge version of MongoEngine, you can get the source from
-`GitHub <http://github.com/mongoengine/mongoengine/>`_ and install it as above:
+`GitHub <http://github.com/hmarr/mongoengine/>`_ and install it as above:
 .. code-block:: console
-    $ git clone git://github.com/mongoengine/mongoengine
+    $ git clone git://github.com/hmarr/mongoengine
    $ cd mongoengine
    $ python setup.py install
--- a/docs/guide/logging-monitoring.rst
+++ b/docs/guide/logging-monitoring.rst
@ -1,80 +0,0 @@
 ==================
 Logging/Monitoring
 ==================
 It is possible to use `pymongo.monitoring <https://api.mongodb.com/python/current/api/pymongo/monitoring.html>`_ to monitor
 the driver events (e.g: queries, connections, etc). This can be handy if you want to monitor the queries issued by
 MongoEngine to the driver.
 To use `pymongo.monitoring` with MongoEngine, you need to make sure that you are registering the listeners
 **before** establishing the database connection (i.e calling `connect`):
 The following snippet provides a basic logging of all command events:
 .. code-block:: python
    import logging
    from pymongo import monitoring
    from mongoengine import *
    log = logging.getLogger()
    log.setLevel(logging.DEBUG)
    logging.basicConfig(level=logging.DEBUG)
    class CommandLogger(monitoring.CommandListener):
        def started(self, event):
            log.debug("Command {0.command_name} with request id "
                     "{0.request_id} started on server "
                     "{0.connection_id}".format(event))
        def succeeded(self, event):
            log.debug("Command {0.command_name} with request id "
                     "{0.request_id} on server {0.connection_id} "
                     "succeeded in {0.duration_micros} "
                     "microseconds".format(event))
        def failed(self, event):
            log.debug("Command {0.command_name} with request id "
                     "{0.request_id} on server {0.connection_id} "
                     "failed in {0.duration_micros} "
                     "microseconds".format(event))
    monitoring.register(CommandLogger())
    class Jedi(Document):
        name = StringField()
    connect()
    log.info('GO!')
    log.info('Saving an item through MongoEngine...')
    Jedi(name='Obi-Wan Kenobii').save()
    log.info('Querying through MongoEngine...')
    obiwan = Jedi.objects.first()
    log.info('Updating through MongoEngine...')
    obiwan.name = 'Obi-Wan Kenobi'
    obiwan.save()
 Executing this prints the following output::
    INFO:root:GO!
    INFO:root:Saving an item through MongoEngine...
    DEBUG:root:Command insert with request id 1681692777 started on server ('localhost', 27017)
    DEBUG:root:Command insert with request id 1681692777 on server ('localhost', 27017) succeeded in 562 microseconds
    INFO:root:Querying through MongoEngine...
    DEBUG:root:Command find with request id 1714636915 started on server ('localhost', 27017)
    DEBUG:root:Command find with request id 1714636915 on server ('localhost', 27017) succeeded in 341 microseconds
    INFO:root:Updating through MongoEngine...
    DEBUG:root:Command update with request id 1957747793 started on server ('localhost', 27017)
    DEBUG:root:Command update with request id 1957747793 on server ('localhost', 27017) succeeded in 455 microseconds
 More details can of course be obtained by checking the `event` argument from the `CommandListener`.
--- a/docs/guide/migration.rst
+++ b/docs/guide/migration.rst
@ -1,308 +0,0 @@
 ===================
 Documents migration
 ===================
 The structure of your documents and their associated mongoengine schemas are likely
 to change over the lifetime of an application. This section provides guidance and
 recommendations on how to deal with migrations.
 Due to the very flexible nature of mongodb, migrations of models aren't trivial and
 for people that know about `alembic` for `sqlalchemy`, there is unfortunately no equivalent
 library that will manage the migration in an automatic fashion for mongoengine.
 Example 1: Addition of a field
 ==============================
 Let's start by taking a simple example of a model change and review the different option you
 have to deal with the migration.
 Let's assume we start with the following schema and save an instance:
 .. code-block:: python
    class User(Document):
        name = StringField()
    User(name="John Doe").save()
    # print the objects as they exist in mongodb
    print(User.objects().as_pymongo())    # [{u'_id': ObjectId('5d06b9c3d7c1f18db3e7c874'), u'name': u'John Doe'}]
 On the next version of your application, let's now assume that a new field `enabled` gets added to the
 existing ``User`` model with a `default=True`. Thus you simply update the ``User`` class to the following:
 .. code-block:: python
    class User(Document):
        name = StringField(required=True)
        enabled = BooleanField(default=True)
 Without applying any migration, we now reload an object from the database into the ``User`` class
 and checks its `enabled` attribute:
 .. code-block:: python
    assert User.objects.count() == 1
    user = User.objects().first()
    assert user.enabled is True
    assert User.objects(enabled=True).count() == 0    # uh?
    assert User.objects(enabled=False).count() == 0   # uh?
    # this is consistent with what we have in the database
    # in fact, 'enabled' does not exist
    print(User.objects().as_pymongo().first())    # {u'_id': ObjectId('5d06b9c3d7c1f18db3e7c874'), u'name': u'John'}
    assert User.objects(enabled=None).count() == 1
 As you can see, even if the document wasn't updated, mongoengine applies the default value seamlessly when it
 loads the pymongo dict into a ``User`` instance. At first sight it looks like you don't need to migrate the
 existing documents when adding new fields but this actually leads to inconsistencies when it comes to querying.
 In fact, when querying, mongoengine isn't trying to account for the default value of the new field and so
 if you don't actually migrate the existing documents, you are taking a risk that querying/updating
 will be missing relevant record.
 When adding fields/modifying default values, you can use any of the following to do the migration
 as a standalone script:
 .. code-block:: python
    # Use mongoengine to set a default value for a given field
    User.objects().update(enabled=True)
    # or use pymongo
    user_coll = User._get_collection()
    user_coll.update_many({}, {'$set': {'enabled': True}})
 Example 2: Inheritance change
 =============================
 Let's consider the following example:
 .. code-block:: python
    class Human(Document):
        name = StringField()
        meta = {"allow_inheritance": True}
    class Jedi(Human):
        dark_side = BooleanField()
        light_saber_color = StringField()
    Jedi(name="Darth Vader", dark_side=True, light_saber_color="red").save()
    Jedi(name="Obi Wan Kenobi", dark_side=False, light_saber_color="blue").save()
    assert Human.objects.count() == 2
    assert Jedi.objects.count() == 2
    # Let's check how these documents got stored in mongodb
    print(Jedi.objects.as_pymongo())
    # [
    #   {'_id': ObjectId('5fac4aaaf61d7fb06046e0f9'), '_cls': 'Human.Jedi', 'name': 'Darth Vader', 'dark_side': True, 'light_saber_color': 'red'},
    #   {'_id': ObjectId('5fac4ac4f61d7fb06046e0fa'), '_cls': 'Human.Jedi', 'name': 'Obi Wan Kenobi', 'dark_side': False, 'light_saber_color': 'blue'}
    # ]
 As you can observe, when you use inheritance, MongoEngine stores a field named '_cls' behind the scene to keep
 track of the Document class.
 Let's now take the scenario that you want to refactor the inheritance schema and:
 - Have the Jedi's with dark_side=True/False become GoodJedi's/DarkSith
 - get rid of the 'dark_side' field
 move to the following schemas:
 .. code-block:: python
    # unchanged
    class Human(Document):
        name = StringField()
        meta = {"allow_inheritance": True}
    # attribute 'dark_side' removed
    class GoodJedi(Human):
        light_saber_color = StringField()
    # new class
    class BadSith(Human):
        light_saber_color = StringField()
 MongoEngine doesn't know about the change or how to map them with the existing data
 so if you don't apply any migration, you will observe a strange behavior, as if the collection was suddenly
 empty.
 .. code-block:: python
    # As a reminder, the documents that we inserted
    # have the _cls field = 'Human.Jedi'
    # Following has no match
    # because the query that is used behind the scene is
    # filtering on {'_cls': 'Human.GoodJedi'}
    assert GoodJedi.objects().count() == 0
    # Following has also no match
    # because it is filtering on {'_cls': {'$in': ('Human', 'Human.GoodJedi', 'Human.BadSith')}}
    # which has no match
    assert Human.objects.count() == 0
    assert Human.objects.first() is None
    # If we bypass MongoEngine and make use of underlying driver (PyMongo)
    # we can see that the documents are there
    humans_coll = Human._get_collection()
    assert humans_coll.count_documents({}) == 2
    # print first document
    print(humans_coll.find_one())
    # {'_id': ObjectId('5fac4aaaf61d7fb06046e0f9'), '_cls': 'Human.Jedi', 'name': 'Darth Vader', 'dark_side': True, 'light_saber_color': 'red'}
 As you can see, first obvious problem is that we need to modify '_cls' values based on existing values of
 'dark_side' documents.
 .. code-block:: python
    humans_coll = Human._get_collection()
    old_class = 'Human.Jedi'
    good_jedi_class = 'Human.GoodJedi'
    bad_sith_class = 'Human.BadSith'
    humans_coll.update_many({'_cls': old_class, 'dark_side': False}, {'$set': {'_cls': good_jedi_class}})
    humans_coll.update_many({'_cls': old_class, 'dark_side': True}, {'$set': {'_cls': bad_sith_class}})
 Let's now check if querying improved in MongoEngine:
 .. code-block:: python
    assert GoodJedi.objects().count() == 1  # Hoorah!
    assert BadSith.objects().count() == 1   # Hoorah!
    assert Human.objects.count() == 2       # Hoorah!
    # let's now check that documents load correctly
    jedi = GoodJedi.objects().first()
    # raises FieldDoesNotExist: The fields "{'dark_side'}" do not exist on the document "Human.GoodJedi"
 In fact we only took care of renaming the _cls values but we havn't removed the 'dark_side' fields
 which does not exist anymore on the GoodJedi's and BadSith's models.
 Let's remove the field from the collections:
 .. code-block:: python
    humans_coll = Human._get_collection()
    humans_coll.update_many({}, {'$unset': {'dark_side': 1}})
 .. note:: We did this migration in 2 different steps for the sake of example but it could have been combined
    with the migration of the _cls fields: ::
        humans_coll.update_many(
            {'_cls': old_class, 'dark_side': False},
            {
                '$set': {'_cls': good_jedi_class},
                '$unset': {'dark_side': 1}
            }
        )
 And verify that the documents now load correctly:
 .. code-block:: python
    jedi = GoodJedi.objects().first()
    assert jedi.name == "Obi Wan Kenobi"
    sith = BadSith.objects().first()
    assert sith.name == "Darth Vader"
 An other way of dealing with this migration is to iterate over
 the documents and update/replace them one by one. This is way slower but
 it is often useful for complex migrations of Document models.
 .. code-block:: python
    for doc in humans_coll.find():
        if doc['_cls'] == 'Human.Jedi':
            doc['_cls'] =  'Human.BadSith' if doc['dark_side'] else 'Human.GoodJedi'
            doc.pop('dark_side')
            humans_coll.replace_one({'_id': doc['_id']}, doc)
 .. warning:: Be aware of this `flaw <https://groups.google.com/g/mongodb-user/c/AFC1ia7MHzk>`_ if you modify documents while iterating
 Example 4: Index removal
 ========================
 If you remove an index from your Document class, or remove an indexed Field from your Document class,
 you'll need to manually drop the corresponding index. MongoEngine will not do that for you.
 The way to deal with this case is to identify the name of the index to drop with `index_information()`, and then drop
 it with `drop_index()`
 Let's for instance assume that you start with the following Document class
 .. code-block:: python
    class User(Document):
        name = StringField(index=True)
        meta = {"indexes": ["name"]}
    User(name="John Doe").save()
 As soon as you start interacting with the Document collection (when `.save()` is called in this case),
 it would create the following indexes:
 .. code-block:: python
    print(User._get_collection().index_information())
    # {
    #  '_id_': {'key': [('_id', 1)], 'v': 2},
    #  'name_1': {'background': False, 'key': [('name', 1)], 'v': 2},
    # }
 Thus: '_id' which is the default index and 'name_1' which is our custom index.
 If you would remove the 'name' field or its index, you would have to call:
 .. code-block:: python
    User._get_collection().drop_index('name_1')
 .. note:: When adding new fields or new indexes, MongoEngine will take care of creating them
    (unless `auto_create_index` is disabled) ::
 Recommendations
 ===============
 - Write migration scripts whenever you do changes to the model schemas
 - Using :class:`~mongoengine.DynamicDocument` or ``meta = {"strict": False}`` may help to avoid some migrations or to have the 2 versions of your application to co-exist.
 - Write post-processing checks to verify that migrations script worked. See below
 Post-processing checks
 ======================
 The following recipe can be used to sanity check a Document collection after you applied migration.
 It does not make any assumption on what was migrated, it will fetch 1000 objects randomly and
 run some quick checks on the documents to make sure the document looks OK. As it is, it will fail
 on the first occurrence of an error but this is something that can be adapted based on your needs.
 .. code-block:: python
    def get_random_oids(collection, sample_size):
        pipeline = [{"$project": {'_id': 1}}, {"$sample": {"size": sample_size}}]
        return [s['_id'] for s in collection.aggregate(pipeline)]
    def get_random_documents(DocCls, sample_size):
        doc_collection = DocCls._get_collection()
        random_oids = get_random_oids(doc_collection, sample_size)
        return DocCls.objects(id__in=random_oids)
    def check_documents(DocCls, sample_size):
        for doc in get_random_documents(DocCls, sample_size):
            # general validation (types and values)
            doc.validate()
            # load all subfields,
            # this may trigger additional queries if you have ReferenceFields
            # so it may be slow
            for field in doc._fields:
                try:
                    getattr(doc, field)
                except Exception:
                    LOG.warning(f"Could not load field {field} in Document {doc.id}")
                    raise
    check_documents(Human, sample_size=1000)
--- a/docs/guide/mongomock.rst
+++ b/docs/guide/mongomock.rst
@ -1,48 +0,0 @@
 ==============================
 Use mongomock for testing
 ==============================
 `mongomock <https://github.com/vmalloc/mongomock/>`_ is a package to do just
 what the name implies, mocking a mongo database.
 To use with mongoengine, simply specify mongomock when connecting with
 mongoengine:
 .. code-block:: python
    connect('mongoenginetest', host='mongomock://localhost')
    conn = get_connection()
 or with an alias:
 .. code-block:: python
    connect('mongoenginetest', host='mongomock://localhost', alias='testdb')
    conn = get_connection('testdb')
 Example of test file:
 ---------------------
 .. code-block:: python
    import unittest
    from mongoengine import connect, disconnect
    class Person(Document):
        name = StringField()
    class TestPerson(unittest.TestCase):
        @classmethod
        def setUpClass(cls):
            connect('mongoenginetest', host='mongomock://localhost')
        @classmethod
        def tearDownClass(cls):
           disconnect()
        def test_thing(self):
            pers = Person(name='John')
            pers.save()
            fresh_pers = Person.objects().first()
            assert fresh_pers.name ==  'John'
--- a/docs/guide/querying.rst
+++ b/docs/guide/querying.rst
@ -15,10 +15,11 @@ fetch documents from the database::
 .. note::
-    As of MongoEngine 0.8 the querysets utilise a local cache.  So iterating
+   Once the iteration finishes (when :class:`StopIteration` is raised),
-    it multiple times will only cause a single query.  If this is not the
+   :meth:`~mongoengine.queryset.QuerySet.rewind` will be called so that the
-    desired behaviour you can call :class:`~mongoengine.QuerySet.no_cache`
+   :class:`~mongoengine.queryset.QuerySet` may be iterated over again. The
-    (version **0.8.3+**) to return a non-caching queryset.
+   results of the first iteration are *not* cached, so the database will be hit
   each time the :class:`~mongoengine.queryset.QuerySet` is iterated over.
 Filtering queries
 =================
@ -39,18 +40,10 @@ syntax::
    # been written by a user whose 'country' field is set to 'uk'
    uk_pages = Page.objects(author__country='uk')
 .. note::
   (version **0.9.1+**) if your field name is like mongodb operator name (for example
   type, lte, lt...) and you want to place it at the end of lookup keyword
   mongoengine automatically  prepend $ to it. To avoid this use  __ at the end of
   your lookup keyword. For example if your field name is ``type`` and you want to
   query by this field you must use ``.objects(user__type__="admin")`` instead of
   ``.objects(user__type="admin")``
 Query operators
 ===============
-Operators other than equality may also be used in queries --- just attach the
+Operators other than equality may also be used in queries; just attach the
 operator name to a key with a double-underscore::
    # Only find users whose age is 18 or less
@ -64,7 +57,7 @@ Available operators are as follows:
 * ``gt`` -- greater than
 * ``gte`` -- greater than or equal to
 * ``not`` -- negate a standard check, may be used before other operators (e.g.
-  ``Q(age__not__mod=(5, 0))``)
+  ``Q(age__not__mod=5)``)
 * ``in`` -- value is in list (a list of values should be provided)
 * ``nin`` -- value is not in list (a list of values should be provided)
 * ``mod`` -- ``value % x == y``, where ``x`` and ``y`` are two provided values
@ -72,9 +65,6 @@ Available operators are as follows:
 * ``size`` -- the size of the array is
 * ``exists`` -- value for field exists
 String queries
 --------------
 The following operators are available as shortcuts to querying with regular
 expressions:
@ -86,81 +76,14 @@ expressions:
 * ``istartswith`` -- string field starts with value (case insensitive)
 * ``endswith`` -- string field ends with value
 * ``iendswith`` -- string field ends with value (case insensitive)
 * ``wholeword`` -- string field contains whole word
 * ``iwholeword`` -- string field contains whole word (case insensitive)
 * ``regex`` -- string field match by regex
 * ``iregex`` -- string field match by regex (case insensitive)
 * ``match``  -- performs an $elemMatch so you can match an entire document within an array
-
+There are a few special operators for performing geographical queries, that
-Geo queries
+may used with :class:`~mongoengine.GeoPointField`\ s:
 -----------
 There are a few special operators for performing geographical queries.
 The following were added in MongoEngine 0.8 for
 :class:`~mongoengine.fields.PointField`,
 :class:`~mongoengine.fields.LineStringField` and
 :class:`~mongoengine.fields.PolygonField`:
 * ``geo_within`` -- check if a geometry is within a polygon. For ease of use
  it accepts either a geojson geometry or just the polygon coordinates eg::
        loc.objects(point__geo_within=[[[40, 5], [40, 6], [41, 6], [40, 5]]])
        loc.objects(point__geo_within={"type": "Polygon",
                                 "coordinates": [[[40, 5], [40, 6], [41, 6], [40, 5]]]})
 * ``geo_within_box`` -- simplified geo_within searching with a box eg::
        loc.objects(point__geo_within_box=[(-125.0, 35.0), (-100.0, 40.0)])
        loc.objects(point__geo_within_box=[<bottom left coordinates>, <upper right coordinates>])
 * ``geo_within_polygon`` -- simplified geo_within searching within a simple polygon eg::
        loc.objects(point__geo_within_polygon=[[40, 5], [40, 6], [41, 6], [40, 5]])
        loc.objects(point__geo_within_polygon=[ [ <x1> , <y1> ] ,
                                                [ <x2> , <y2> ] ,
                                                [ <x3> , <y3> ] ])
 * ``geo_within_center`` -- simplified geo_within the flat circle radius of a point eg::
        loc.objects(point__geo_within_center=[(-125.0, 35.0), 1])
        loc.objects(point__geo_within_center=[ [ <x>, <y> ] , <radius> ])
 * ``geo_within_sphere`` -- simplified geo_within the spherical circle radius of a point eg::
        loc.objects(point__geo_within_sphere=[(-125.0, 35.0), 1])
        loc.objects(point__geo_within_sphere=[ [ <x>, <y> ] , <radius> ])
 * ``geo_intersects`` -- selects all locations that intersect with a geometry eg::
        # Inferred from provided points lists:
        loc.objects(poly__geo_intersects=[40, 6])
        loc.objects(poly__geo_intersects=[[40, 5], [40, 6]])
        loc.objects(poly__geo_intersects=[[[40, 5], [40, 6], [41, 6], [41, 5], [40, 5]]])
        # With geoJson style objects
        loc.objects(poly__geo_intersects={"type": "Point", "coordinates": [40, 6]})
        loc.objects(poly__geo_intersects={"type": "LineString",
                                          "coordinates": [[40, 5], [40, 6]]})
        loc.objects(poly__geo_intersects={"type": "Polygon",
                                          "coordinates": [[[40, 5], [40, 6], [41, 6], [41, 5], [40, 5]]]})
 * ``near`` -- find all the locations near a given point::
        loc.objects(point__near=[40, 5])
        loc.objects(point__near={"type": "Point", "coordinates": [40, 5]})
  You can also set the maximum and/or the minimum distance in meters as well::
        loc.objects(point__near=[40, 5], point__max_distance=1000)
        loc.objects(point__near=[40, 5], point__min_distance=100)
 The older 2D indexes are still supported with the
 :class:`~mongoengine.fields.GeoPointField`:
 * ``within_distance`` -- provide a list containing a point and a maximum
  distance (e.g. [(41.342, -87.653), 5])
-* ``within_spherical_distance`` -- same as above but using the spherical geo model
+* ``within_spherical_distance`` -- Same as above but using the spherical geo model
  (e.g. [(41.342, -87.653), 5/earth_radius])
 * ``near`` -- order the documents by how close they are to a given point
 * ``near_sphere`` -- Same as above but using the spherical geo model
@ -168,19 +91,14 @@ The older 2D indexes are still supported with the
  [(35.0, -125.0), (40.0, -100.0)])
 * ``within_polygon`` -- filter documents to those within a given polygon (e.g.
  [(41.91,-87.69), (41.92,-87.68), (41.91,-87.65), (41.89,-87.65)]).
  .. note:: Requires Mongo Server 2.0
 * ``max_distance`` -- can be added to your location queries to set a maximum
  distance.
 * ``min_distance`` -- can be added to your location queries to set a minimum
  distance.
 Querying lists
 --------------
 On most fields, this syntax will look up documents where the field specified
 matches the given value exactly, but when the field refers to a
-:class:`~mongoengine.fields.ListField`, a single item may be provided, in which case
+:class:`~mongoengine.ListField`, a single item may be provided, in which case
 lists that contain that item will be matched::
    class Page(Document):
@ -211,14 +129,12 @@ However, this doesn't map well to the syntax so you can also use a capital S ins
    Post.objects(comments__by="joe").update(inc__comments__S__votes=1)
-.. note::
+    .. note:: Due to Mongo currently the $ operator only applies to the first matched item in the query.
    Due to :program:`Mongo`, currently the $ operator only applies to the
    first matched item in the query.
 Raw queries
 -----------
-It is possible to provide a raw :mod:`PyMongo` query as a query parameter, which will
+It is possible to provide a raw PyMongo query as a query parameter, which will
 be integrated directly into the query. This is done using the ``__raw__``
 keyword argument::
@ -226,26 +142,14 @@ keyword argument::
 .. versionadded:: 0.4
 Sorting/Ordering results
 ========================
 It is possible to order the results by 1 or more keys using :meth:`~mongoengine.queryset.QuerySet.order_by`.
 The order may be specified by prepending each of the keys by "+" or "-". Ascending order is assumed if there's no prefix.::
    # Order by ascending date
    blogs = BlogPost.objects().order_by('date')    # equivalent to .order_by('+date')
    # Order by ascending date first, then descending title
    blogs = BlogPost.objects().order_by('+date', '-title')
 Limiting and skipping results
 =============================
-Just as with traditional ORMs, you may limit the number of results returned or
+Just as with traditional ORMs, you may limit the number of results returned, or
 skip a number or results in you query.
 :meth:`~mongoengine.queryset.QuerySet.limit` and
-:meth:`~mongoengine.queryset.QuerySet.skip` methods are available on
+:meth:`~mongoengine.queryset.QuerySet.skip` and methods are available on
-:class:`~mongoengine.queryset.QuerySet` objects, but the `array-slicing` syntax
+:class:`~mongoengine.queryset.QuerySet` objects, but the prefered syntax for
-is preferred for achieving this::
+achieving this is using array-slicing syntax::
    # Only the first 5 people
    users = User.objects[:5]
@ -253,7 +157,7 @@ is preferred for achieving this::
    # All except for the first 5 people
    users = User.objects[5:]
-    # 5 users, starting from the 11th user found
+    # 5 users, starting from the 10th user found
    users = User.objects[10:15]
 You may also index the query to retrieve a single result. If an item at that
@ -275,21 +179,25 @@ Retrieving unique results
 -------------------------
 To retrieve a result that should be unique in the collection, use
 :meth:`~mongoengine.queryset.QuerySet.get`. This will raise
-:class:`~mongoengine.queryset.DoesNotExist` if
+:class:`~mongoengine.queryset.DoesNotExist` if no document matches the query,
-no document matches the query, and
+and :class:`~mongoengine.queryset.MultipleObjectsReturned` if more than one
-:class:`~mongoengine.queryset.MultipleObjectsReturned`
+document matched the query.
 if more than one document matched the query.  These exceptions are merged into
 your document definitions eg: `MyDoc.DoesNotExist`
-A variation of this method, get_or_create() existed, but it was unsafe. It
+A variation of this method exists,
-could not be made safe, because there are no transactions in mongoDB. Other
+:meth:`~mongoengine.queryset.Queryset.get_or_create`, that will create a new
-approaches should be investigated, to ensure you don't accidentally duplicate
+document with the query arguments if no documents match the query. An
-data when using something similar to this method. Therefore it was deprecated
+additional keyword argument, :attr:`defaults` may be provided, which will be
-in 0.8 and removed in 0.10.
+used as default values for the new document, in the case that it should need
 to be created::
    >>> a, created = User.objects.get_or_create(name='User A', defaults={'age': 30})
    >>> b, created = User.objects.get_or_create(name='User A', defaults={'age': 40})
    >>> a.name == b.name and a.age == b.age
    True
 Default Document queries
 ========================
-By default, the objects :attr:`~Document.objects` attribute on a
+By default, the objects :attr:`~mongoengine.Document.objects` attribute on a
 document returns a :class:`~mongoengine.queryset.QuerySet` that doesn't filter
 the collection -- it returns all objects. This may be changed by defining a
 method on a document that modifies a queryset. The method should accept two
@ -332,7 +240,7 @@ Should you want to add custom methods for interacting with or filtering
 documents, extending the :class:`~mongoengine.queryset.QuerySet` class may be
 the way to go. To use a custom :class:`~mongoengine.queryset.QuerySet` class on
 a document, set ``queryset_class`` to the custom class in a
-:class:`~mongoengine.Document`'s ``meta`` dictionary::
+:class:`~mongoengine.Document`\ s ``meta`` dictionary::
    class AwesomerQuerySet(QuerySet):
@ -356,19 +264,12 @@ Javascript code that is executed on the database server.
 Counting results
 ----------------
-Just as with limiting and skipping results, there is a method on a
+Just as with limiting and skipping results, there is a method on
-:class:`~mongoengine.queryset.QuerySet` object --
+:class:`~mongoengine.queryset.QuerySet` objects --
-:meth:`~mongoengine.queryset.QuerySet.count`::
+:meth:`~mongoengine.queryset.QuerySet.count`, but there is also a more Pythonic
 way of achieving this::
-    num_users = User.objects.count()
+    num_users = len(User.objects)
 You could technically use ``len(User.objects)`` to get the same result, but it
 would be significantly slower than :meth:`~mongoengine.queryset.QuerySet.count`.
 When you execute a server-side count query, you let MongoDB do the heavy
 lifting and you receive a single integer over the wire. Meanwhile, ``len()``
 retrieves all the results, places them in a local cache, and finally counts
 them. If we compare the performance of the two operations, ``len()`` is much slower
 than :meth:`~mongoengine.queryset.QuerySet.count`.
 Further aggregation
 -------------------
@ -402,25 +303,6 @@ would be generating "tag-clouds"::
    top_tags = sorted(tag_freqs.items(), key=itemgetter(1), reverse=True)[:10]
 MongoDB aggregation API
 -----------------------
 If you need to run aggregation pipelines, MongoEngine provides an entry point to `Pymongo's aggregation framework <https://api.mongodb.com/python/current/examples/aggregation.html#aggregation-framework>`_
 through :meth:`~mongoengine.queryset.QuerySet.aggregate`. Check out Pymongo's documentation for the syntax and pipeline.
 An example of its use would be::
        class Person(Document):
            name = StringField()
        Person(name='John').save()
        Person(name='Bob').save()
        pipeline = [
            {"$sort" : {"name" : -1}},
            {"$project": {"_id": 0, "name": {"$toUpper": "$name"}}}
            ]
        data = Person.objects().aggregate(pipeline)
        assert data == [{'name': 'BOB'}, {'name': 'JOHN'}]
 Query efficiency and performance
 ================================
@ -433,7 +315,7 @@ Retrieving a subset of fields
 Sometimes a subset of fields on a :class:`~mongoengine.Document` is required,
 and for efficiency only these should be retrieved from the database. This issue
 is especially important for MongoDB, as fields may often be extremely large
-(e.g. a :class:`~mongoengine.fields.ListField` of
+(e.g. a :class:`~mongoengine.ListField` of
 :class:`~mongoengine.EmbeddedDocument`\ s, which represent the comments on a
 blog post. To select only a subset of fields, use
 :meth:`~mongoengine.queryset.QuerySet.only`, specifying the fields you want to
@ -465,14 +347,14 @@ If you later need the missing fields, just call
 Getting related data
 --------------------
-When iterating the results of :class:`~mongoengine.fields.ListField` or
+When iterating the results of :class:`~mongoengine.ListField` or
-:class:`~mongoengine.fields.DictField` we automatically dereference any
+:class:`~mongoengine.DictField` we automatically dereference any
 :class:`~pymongo.dbref.DBRef` objects as efficiently as possible, reducing the
 number the queries to mongo.
 There are times when that efficiency is not enough, documents that have
-:class:`~mongoengine.fields.ReferenceField` objects or
+:class:`~mongoengine.ReferenceField` objects or
-:class:`~mongoengine.fields.GenericReferenceField` objects at the top level are
+:class:`~mongoengine.GenericReferenceField` objects at the top level are
 expensive as the number of queries to MongoDB can quickly rise.
 To limit the number of queries use
@ -483,30 +365,8 @@ references to the depth of 1 level.  If you have more complicated documents and
 want to dereference more of the object at once then increasing the :attr:`max_depth`
 will dereference more levels of the document.
 Turning off dereferencing
 -------------------------
 Sometimes for performance reasons you don't want to automatically dereference
 data. To turn off dereferencing of the results of a query use
 :func:`~mongoengine.queryset.QuerySet.no_dereference` on the queryset like so::
    post = Post.objects.no_dereference().first()
    assert(isinstance(post.author, DBRef))
 You can also turn off all dereferencing for a fixed period by using the
 :class:`~mongoengine.context_managers.no_dereference` context manager::
    with no_dereference(Post) as Post:
        post = Post.objects.first()
        assert(isinstance(post.author, DBRef))
    # Outside the context manager dereferencing occurs.
    assert(isinstance(post.author, User))
 Advanced queries
 ================
 Sometimes calling a :class:`~mongoengine.queryset.QuerySet` object with keyword
 arguments can't fully express the query you want to use -- for example if you
 need to combine a number of constraints using *and* and *or*. This is made
@ -519,49 +379,33 @@ operators. To use a :class:`~mongoengine.queryset.Q` object, pass it in as the
 first positional argument to :attr:`Document.objects` when you filter it by
 calling it with keyword arguments::
    from mongoengine.queryset.visitor import Q
    # Get published posts
    Post.objects(Q(published=True) | Q(publish_date__lte=datetime.now()))
    # Get top posts
    Post.objects((Q(featured=True) & Q(hits__gte=1000)) | Q(hits__gte=5000))
 .. warning:: You have to use bitwise operators.  You cannot use ``or``, ``and``
    to combine queries as ``Q(a=a) or Q(b=b)`` is not the same as
    ``Q(a=a) | Q(b=b)``. As ``Q(a=a)`` equates to true ``Q(a=a) or Q(b=b)`` is
    the same as ``Q(a=a)``.
 .. _guide-atomic-updates:
 Atomic updates
 ==============
 Documents may be updated atomically by using the
-:meth:`~mongoengine.queryset.QuerySet.update_one`,
+:meth:`~mongoengine.queryset.QuerySet.update_one` and
-:meth:`~mongoengine.queryset.QuerySet.update` and
+:meth:`~mongoengine.queryset.QuerySet.update` methods on a
-:meth:`~mongoengine.queryset.QuerySet.modify` methods on a
+:meth:`~mongoengine.queryset.QuerySet`. There are several different "modifiers"
-:class:`~mongoengine.queryset.QuerySet` or
+that you may use with these methods:
 :meth:`~mongoengine.Document.modify` and
 :meth:`~mongoengine.Document.save` (with :attr:`save_condition` argument) on a
 :class:`~mongoengine.Document`.
 There are several different "modifiers" that you may use with these methods:
 * ``set`` -- set a particular value
-* ``set_on_insert`` -- set only if this is new document  `need to add upsert=True`_
+* ``unset`` -- delete a particular value (since MongoDB v1.3+)
 * ``unset`` -- delete a particular value (since MongoDB v1.3)
 * ``max`` -- update only if value is bigger
 * ``min`` -- update only if value is smaller
 * ``inc`` -- increment a value by a given amount
 * ``dec`` -- decrement a value by a given amount
 * ``pop`` -- remove the last item from a list
 * ``push`` -- append a value to a list
 * ``push_all`` -- append several values to a list
-* ``pop`` -- remove the first or last element of a list `depending on the value`_
+* ``pop`` -- remove the first or last element of a list
 * ``pull`` -- remove a value from a list
 * ``pull_all`` -- remove several values from a list
 * ``add_to_set`` -- add value to a list only if its not in the list already
 * ``rename`` -- rename the key name
 .. _depending on the value: http://docs.mongodb.org/manual/reference/operator/update/pop/
 The syntax for atomic updates is similar to the querying syntax, but the
 modifier comes before the field, not after it::
@ -581,14 +425,7 @@ modifier comes before the field, not after it::
    >>> post.tags
    ['database', 'nosql']
-.. note::
+.. note ::
    If no modifier operator is specified the default will be ``$set``. So the following sentences are identical::
        >>> BlogPost.objects(id=post.id).update(title='Example Post')
        >>> BlogPost.objects(id=post.id).update(set__title='Example Post')
 .. note::
    In version 0.5 the :meth:`~mongoengine.Document.save` runs atomic updates
    on changed documents by tracking changes to that document.
@ -604,20 +441,10 @@ cannot use the `$` syntax in keyword arguments it has been mapped to `S`::
    >>> post.tags
    ['database', 'mongodb']
-From MongoDB version 2.6, push operator supports $position value which allows
+.. note ::
 to push values with index::
    >>> post = BlogPost(title="Test", tags=["mongo"])
    >>> post.save()
    >>> post.update(push__tags__0=["database", "code"])
    >>> post.reload()
    >>> post.tags
    ['database', 'code', 'mongo']
 .. note::
    Currently only top level lists are handled, future versions of mongodb /
    pymongo plan to support nested positional operators.  See `The $ positional
-    operator <https://docs.mongodb.com/manual/tutorial/update-documents/#Updating-The%24positionaloperator>`_.
+    operator <http://www.mongodb.org/display/DOCS/Updating#Updating-The%24positionaloperator>`_.
 Server-side javascript execution
 ================================
@ -656,7 +483,7 @@ Some variables are made available in the scope of the Javascript function:
 The following example demonstrates the intended usage of
 :meth:`~mongoengine.queryset.QuerySet.exec_js` by defining a function that sums
-over a field on a document (this functionality is already available through
+over a field on a document (this functionality is already available throught
 :meth:`~mongoengine.queryset.QuerySet.sum` but is shown here for sake of
 example)::
@ -683,7 +510,7 @@ Javascript code. When accessing a field on a collection object, use
 square-bracket notation, and prefix the MongoEngine field name with a tilde.
 The field name that follows the tilde will be translated to the name used in
 the database. Note that when referring to fields on embedded documents,
-the name of the :class:`~mongoengine.fields.EmbeddedDocumentField`, followed by a dot,
+the name of the :class:`~mongoengine.EmbeddedDocumentField`, followed by a dot,
 should be used before the name of the field on the embedded document. The
 following example shows how the substitutions are made::
--- a/docs/guide/signals.rst
+++ b/docs/guide/signals.rst
@ -1,6 +1,5 @@
 .. _signals:
 =======
 Signals
 =======
@ -8,95 +7,32 @@ Signals
 .. note::
-  Signal support is provided by the excellent `blinker`_ library. If you wish
+  Signal support is provided by the excellent `blinker`_ library and
-  to enable signal support this library must be installed, though it is not
+  will gracefully fall back if it is not available.
  required for MongoEngine to function.
 Overview
 --------
-Signals are found within the `mongoengine.signals` module.  Unless
+The following document signals exist in MongoEngine and are pretty self-explanatory:
 specified signals receive no additional arguments beyond the `sender` class and
 `document` instance.  Post-signals are only called if there were no exceptions
 raised during the processing of their related function.
-Available signals include:
+  * `mongoengine.signals.pre_init`
  * `mongoengine.signals.post_init`
  * `mongoengine.signals.pre_save`
  * `mongoengine.signals.post_save`
  * `mongoengine.signals.pre_delete`
  * `mongoengine.signals.post_delete`
  * `mongoengine.signals.pre_bulk_insert`
  * `mongoengine.signals.post_bulk_insert`
-`pre_init`
+Example usage::
  Called during the creation of a new :class:`~mongoengine.Document` or
  :class:`~mongoengine.EmbeddedDocument` instance, after the constructor
  arguments have been collected but before any additional processing has been
  done to them.  (I.e. assignment of default values.)  Handlers for this signal
  are passed the dictionary of arguments using the `values` keyword argument
  and may modify this dictionary prior to returning.
 `post_init`
  Called after all processing of a new :class:`~mongoengine.Document` or
  :class:`~mongoengine.EmbeddedDocument` instance has been completed.
 `pre_save`
  Called within :meth:`~mongoengine.Document.save` prior to performing
  any actions.
 `pre_save_post_validation`
  Called within :meth:`~mongoengine.Document.save` after validation
  has taken place but before saving.
 `post_save`
  Called within :meth:`~mongoengine.Document.save` after most actions
  (validation, insert/update, and cascades, but not clearing dirty flags) have
  completed successfully.  Passed the additional boolean keyword argument
  `created` to indicate if the save was an insert or an update.
 `pre_delete`
  Called within :meth:`~mongoengine.Document.delete` prior to
  attempting the delete operation.
 `post_delete`
  Called within :meth:`~mongoengine.Document.delete` upon successful
  deletion of the record.
 `pre_bulk_insert`
  Called after validation of the documents to insert, but prior to any data
  being written. In this case, the `document` argument is replaced by a
  `documents` argument representing the list of documents being inserted.
 `post_bulk_insert`
  Called after a successful bulk insert operation.  As per `pre_bulk_insert`,
  the `document` argument is omitted and replaced with a `documents` argument.
  An additional boolean argument, `loaded`, identifies the contents of
  `documents` as either :class:`~mongoengine.Document` instances when `True` or
  simply a list of primary key values for the inserted records if `False`.
 Attaching Events
 ----------------
 After writing a handler function like the following::
    import logging
    from datetime import datetime
    from mongoengine import *
    from mongoengine import signals
    def update_modified(sender, document):
        document.modified = datetime.utcnow()
 You attach the event handler to your :class:`~mongoengine.Document` or
 :class:`~mongoengine.EmbeddedDocument` subclass::
    class Record(Document):
        modified = DateTimeField()
    signals.pre_save.connect(update_modified)
 While this is not the most elaborate document model, it does demonstrate the
 concepts involved.  As a more complete demonstration you can also define your
 handlers within your subclass::
    class Author(Document):
        name = StringField()
        def __unicode__(self):
            return self.name
        @classmethod
        def pre_save(cls, sender, document, **kwargs):
            logging.debug("Pre Save: %s" % document.name)
@ -113,37 +49,5 @@ handlers within your subclass::
    signals.pre_save.connect(Author.pre_save, sender=Author)
    signals.post_save.connect(Author.post_save, sender=Author)
 .. warning::
    Note that EmbeddedDocument only supports pre/post_init signals. pre/post_save, etc should be attached to Document's class only. Attaching pre_save to an EmbeddedDocument is ignored silently.
 Finally, you can also use this small decorator to quickly create a number of
 signals and attach them to your :class:`~mongoengine.Document` or
 :class:`~mongoengine.EmbeddedDocument` subclasses as class decorators::
    def handler(event):
        """Signal decorator to allow use of callback functions as class decorators."""
        def decorator(fn):
            def apply(cls):
                event.connect(fn, sender=cls)
                return cls
            fn.apply = apply
            return fn
        return decorator
 Using the first example of updating a modification time the code is now much
 cleaner looking while still allowing manual execution of the callback::
    @handler(signals.pre_save)
    def update_modified(sender, document):
        document.modified = datetime.utcnow()
    @update_modified.apply
    class Record(Document):
        modified = DateTimeField()
 .. _blinker: http://pypi.python.org/pypi/blinker
--- a/docs/guide/text-indexes.rst
+++ b/docs/guide/text-indexes.rst
@ -1,51 +0,0 @@
 ===========
 Text Search
 ===========
 After MongoDB 2.4 version, supports search documents by text indexes.
 Defining a Document with text index
 ===================================
 Use the *$* prefix to set a text index, Look the declaration::
  class News(Document):
      title = StringField()
      content = StringField()
      is_active = BooleanField()
      meta = {'indexes': [
          {'fields': ['$title', "$content"],
           'default_language': 'english',
           'weights': {'title': 10, 'content': 2}
          }
      ]}
 Querying
 ========
 Saving a document::
  News(title="Using mongodb text search",
       content="Testing text search").save()
  News(title="MongoEngine 0.9 released",
       content="Various improvements").save()
 Next, start a text search using :attr:`QuerySet.search_text` method::
  document = News.objects.search_text('testing').first()
  document.title # may be: "Using mongodb text search"
  document = News.objects.search_text('released').first()
  document.title # may be: "MongoEngine 0.9 released"
 Ordering by text score
 ======================
 ::
  objects = News.objects.search_text('mongo').order_by('$text_score')
--- a/docs/guide/validation.rst
+++ b/docs/guide/validation.rst
@ -1,122 +0,0 @@
 ====================
 Document Validation
 ====================
 By design, MongoEngine strictly validates the documents right before they are inserted in MongoDB
 and makes sure they are consistent with the fields defined in your models.
 MongoEngine makes the assumption that the documents that exists in the DB are compliant with the schema.
 This means that Mongoengine will not validate a document when an object is loaded from the DB into an instance
 of your model but this operation may fail under some circumstances (e.g. if there is a field in
 the document fetched from the database that is not defined in your model).
 Built-in validation
 ===================
 Mongoengine provides different fields that encapsulate the corresponding validation
 out of the box. Validation runs when calling `.validate()` or `.save()`
 .. code-block:: python
    from mongoengine import Document, EmailField
    class User(Document):
        email = EmailField()
        age = IntField(min_value=0, max_value=99)
    user = User(email='invalid@', age=24)
    user.validate()     # raises ValidationError (Invalid email address: ['email'])
    user.save()         # raises ValidationError (Invalid email address: ['email'])
    user2 = User(email='john.doe@garbage.com', age=1000)
    user2.save()        # raises ValidationError (Integer value is too large: ['age'])
 Custom validation
 =================
 The following feature can be used to customize the validation:
 * Field `validation` parameter
 .. code-block:: python
    def not_john_doe(name):
        if name == 'John Doe':
            raise ValidationError("John Doe is not a valid name")
    class Person(Document):
        full_name = StringField(validation=not_john_doe)
    Person(full_name='Billy Doe').save()
    Person(full_name='John Doe').save()  # raises ValidationError (John Doe is not a valid name)
 * Document `clean` method
 This method is called as part of :meth:`~mongoengine.document.Document.save` and should be used to provide
 custom model validation and/or to modify some of the field values prior to validation.
 For instance, you could use it to automatically provide a value for a field, or to do validation
 that requires access to more than a single field.
 .. code-block:: python
    class Essay(Document):
        status = StringField(choices=('Published', 'Draft'), required=True)
        pub_date = DateTimeField()
        def clean(self):
            # Validate that only published essays have a `pub_date`
            if self.status == 'Draft' and self.pub_date is not None:
                raise ValidationError('Draft entries should not have a publication date.')
            # Set the pub_date for published items if not set.
            if self.status == 'Published' and self.pub_date is None:
                self.pub_date = datetime.now()
 .. note::
    Cleaning is only called if validation is turned on and when calling
    :meth:`~mongoengine.Document.save`.
 * Adding custom Field classes
 We recommend as much as possible to use fields provided by MongoEngine. However, it is also possible
 to subclass a Field and encapsulate some validation by overriding the `validate` method
 .. code-block:: python
    class AgeField(IntField):
        def validate(self, value):
            super(AgeField, self).validate(value)     # let IntField.validate run first
            if value == 60:
                self.error('60 is not allowed')
    class Person(Document):
        age = AgeField(min_value=0, max_value=99)
    Person(age=20).save()   # passes
    Person(age=1000).save() # raises ValidationError (Integer value is too large: ['age'])
    Person(age=60).save()   # raises ValidationError (Person:None) (60 is not allowed: ['age'])
 .. note::
   When overriding `validate`, use `self.error("your-custom-error")` instead of raising ValidationError explicitly,
   it will provide a better context with the error message
 Skipping validation
 ====================
 Although discouraged as it allows to violate fields constraints, if for some reason you need to disable
 the validation and cleaning of a document when you call :meth:`~mongoengine.document.Document.save`, you can use `.save(validate=False)`.
 .. code-block:: python
    class Person(Document):
        age = IntField(max_value=100)
    Person(age=1000).save()    # raises ValidationError (Integer value is too large)
    Person(age=1000).save(validate=False)
    person = Person.objects.first()
    assert person.age == 1000
--- a/docs/index.rst
+++ b/docs/index.rst
@ -7,83 +7,56 @@ MongoDB. To install it, simply run
 .. code-block:: console
-    $ python -m pip install -U mongoengine
+    # pip install -U mongoengine
 :doc:`tutorial`
-  A quick tutorial building a tumblelog to get you up and running with
+  Start here for a quick overview.
  MongoEngine.
 :doc:`guide/index`
-  The Full guide to MongoEngine --- from modeling documents to storing files,
+  The Full guide to MongoEngine
  from querying for data to firing signals and *everything* between.
 :doc:`apireference`
-  The complete API documentation --- the innards of documents, querysets and fields.
+  The complete API documentation.
 :doc:`upgrade`
  How to upgrade MongoEngine.
 :doc:`faq`
  Frequently Asked Questions
 :doc:`django`
  Using MongoEngine and Django
 MongoDB and driver support
 --------------------------
 MongoEngine is based on the PyMongo driver and tested against multiple versions of MongoDB.
 For further details, please refer to the `readme <https://github.com/MongoEngine/mongoengine#mongoengine>`_.
 Community
 ---------
 To get help with using MongoEngine, use the `MongoEngine Users mailing list
-<http://groups.google.com/group/mongoengine-users>`_ or the ever popular
+<http://groups.google.com/group/mongoengine-users>`_ or come chat on the
-`stackoverflow <http://www.stackoverflow.com>`_.
+`#mongoengine IRC channel <irc://irc.freenode.net/mongoengine>`_.
 Contributing
 ------------
-**Yes please!**  We are always looking for contributions, additions and improvements.
+The source is available on `GitHub <http://github.com/hmarr/mongoengine>`_ and
-
+contributions are always encouraged. Contributions can be as simple as
-The source is available on `GitHub <http://github.com/MongoEngine/mongoengine>`_
+minor tweaks to this documentation. To contribute, fork the project on
-and contributions are always encouraged. Contributions can be as simple as
+`GitHub <http://github.com/hmarr/mongoengine>`_ and send a
 minor tweaks to this documentation, the website or the core.
 To contribute, fork the project on
 `GitHub <http://github.com/MongoEngine/mongoengine>`_ and send a
 pull request.
 Also, you can join the developers' `mailing list
 <http://groups.google.com/group/mongoengine-dev>`_.
 Changes
 -------
 See the :doc:`changelog` for a full list of changes to MongoEngine and
 :doc:`upgrade` for upgrade information.
 .. note::  Always read and test the `upgrade <upgrade>`_ documentation before
    putting updates live in production **;)**
 Offline Reading
 ---------------
 Download the docs in `pdf <https://media.readthedocs.org/pdf/mongoengine-odm/latest/mongoengine-odm.pdf>`_
 or `epub <https://media.readthedocs.org/epub/mongoengine-odm/latest/mongoengine-odm.epub>`_
 formats for offline reading.
 .. toctree::
-    :maxdepth: 1
+   :hidden:
    :numbered:
    :hidden:
-    tutorial
+   tutorial
-    guide/index
+   guide/index
-    apireference
+   apireference
-    changelog
+   django
-    upgrade
+   changelog
-    faq
+   upgrade
    django
 Indices and tables
 ------------------
@ -91,3 +64,4 @@ Indices and tables
 * :ref:`genindex`
 * :ref:`modindex`
 * :ref:`search`
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@ -1,3 +0,0 @@
 Sphinx==3.3.0
 sphinx-rtd-theme==0.5.0
 readthedocs-sphinx-ext==2.1.1
--- a/docs/tutorial.rst
+++ b/docs/tutorial.rst
@ -1,83 +1,73 @@
 ========
 Tutorial
 ========
 This tutorial introduces **MongoEngine** by means of example --- we will walk
-through how to create a simple **Tumblelog** application. A tumblelog is a
+through how to create a simple **Tumblelog** application. A Tumblelog is a type
-blog that supports mixed media content, including text, images, links, video,
+of blog where posts are not constrained to being conventional text-based posts.
-audio, etc. For simplicity's sake, we'll stick to text, image, and link
+As well as text-based entries, users may post images, links, videos, etc. For
-entries. As the purpose of this tutorial is to introduce MongoEngine, we'll
+simplicity's sake, we'll stick to text, image and link entries in our
 application. As the purpose of this tutorial is to introduce MongoEngine, we'll
 focus on the data-modelling side of the application, leaving out a user
 interface.
 Getting started
 ===============
 Before we start, make sure that a copy of MongoDB is running in an accessible
 location --- running it locally will be easier, but if that is not an option
-then it may be run on a remote server. If you haven't installed MongoEngine,
+then it may be run on a remote server.
 simply use pip to install it like so::
    $ python -m pip install mongoengine
 Before we can start using MongoEngine, we need to tell it how to connect to our
 instance of :program:`mongod`. For this we use the :func:`~mongoengine.connect`
-function. If running locally, the only argument we need to provide is the name
+function. The only argument we need to provide is the name of the MongoDB
-of the MongoDB database to use::
+database to use::
    from mongoengine import *
    connect('tumblelog')
-There are lots of options for connecting to MongoDB, for more information about
+For more information about connecting to MongoDB see :ref:`guide-connecting`.
 them see the :ref:`guide-connecting` guide.
 Defining our documents
 ======================
 MongoDB is *schemaless*, which means that no schema is enforced by the database
 --- we may add and remove fields however we want and MongoDB won't complain.
 This makes life a lot easier in many regards, especially when there is a change
-to the data model. However, defining schemas for our documents can help to iron
+to the data model. However, defining schemata for our documents can help to
-out bugs involving incorrect types or missing fields, and also allow us to
+iron out bugs involving incorrect types or missing fields, and also allow us to
 define utility methods on our documents in the same way that traditional
 :abbr:`ORMs (Object-Relational Mappers)` do.
 In our Tumblelog application we need to store several different types of
-information. We will need to have a collection of **users**, so that we may
+information.  We will need to have a collection of **users**, so that we may
-link posts to an individual. We also need to store our different types of
+link posts to an individual. We also need to store our different types
-**posts** (eg: text, image and link) in the database. To aid navigation of our
+**posts** (text, image and link) in the database. To aid navigation of our
 Tumblelog, posts may have **tags** associated with them, so that the list of
 posts shown to the user may be limited to posts that have been assigned a
-specific tag. Finally, it would be nice if **comments** could be added to
+specified tag.  Finally, it would be nice if **comments** could be added to
-posts. We'll start with **users**, as the other document models are slightly
+posts. We'll start with **users**, as the others are slightly more involved.
 more involved.
 Users
 -----
 Just as if we were using a relational database with an ORM, we need to define
-which fields a :class:`User` may have, and what types of data they might store::
+which fields a :class:`User` may have, and what their types will be::
    class User(Document):
        email = StringField(required=True)
        first_name = StringField(max_length=50)
        last_name = StringField(max_length=50)
-This looks similar to how the structure of a table would be defined in a
+This looks similar to how a the structure of a table would be defined in a
 regular ORM. The key difference is that this schema will never be passed on to
-MongoDB --- this will only be enforced at the application level, making future
+MongoDB --- this will only be enforced at the application level. Also, the User
-changes easy to manage. Also, the User documents will be stored in a
+documents will be stored in a MongoDB *collection* rather than a table.
 MongoDB *collection* rather than a table.
 Posts, Comments and Tags
 ------------------------
 Now we'll think about how to store the rest of the information. If we were
 using a relational database, we would most likely have a table of **posts**, a
 table of **comments** and a table of **tags**.  To associate the comments with
 individual posts, we would put a column in the comments table that contained a
-foreign key to the posts table. We'd also need a link table to provide the
+foreign key to the posts table.  We'd also need a link table to provide the
 many-to-many relationship between posts and tags. Then we'd need to address the
 problem of storing the specialised post-types (text, image and link). There are
 several ways we can achieve this, but each of them have their problems --- none
@ -85,25 +75,21 @@ of them stand out as particularly intuitive solutions.
 Posts
 ^^^^^
-
+But MongoDB *isn't* a relational database, so we're not going to do it that
 Happily MongoDB *isn't* a relational database, so we're not going to do it that
 way. As it turns out, we can use MongoDB's schemaless nature to provide us with
-a much nicer solution. We will store all of the posts in *one collection* and
+a much nicer solution. We will store all of the posts in *one collection* ---
-each post type will only store the fields it needs. If we later want to add
+each post type will just have the fields it needs. If we later want to add
 video posts, we don't have to modify the collection at all, we just *start
 using* the new fields we need to support video posts. This fits with the
 Object-Oriented principle of *inheritance* nicely. We can think of
 :class:`Post` as a base class, and :class:`TextPost`, :class:`ImagePost` and
 :class:`LinkPost` as subclasses of :class:`Post`. In fact, MongoEngine supports
-this kind of modeling out of the box --- all you need do is turn on inheritance
+this kind of modelling out of the box::
 by setting :attr:`allow_inheritance` to True in the :attr:`meta`::
    class Post(Document):
        title = StringField(max_length=120, required=True)
        author = ReferenceField(User)
        meta = {'allow_inheritance': True}
    class TextPost(Post):
        content = StringField()
@ -114,21 +100,20 @@ by setting :attr:`allow_inheritance` to True in the :attr:`meta`::
        link_url = StringField()
 We are storing a reference to the author of the posts using a
-:class:`~mongoengine.fields.ReferenceField` object. These are similar to foreign key
+:class:`~mongoengine.ReferenceField` object. These are similar to foreign key
 fields in traditional ORMs, and are automatically translated into references
 when they are saved, and dereferenced when they are loaded.
 Tags
 ^^^^
 Now that we have our Post models figured out, how will we attach tags to them?
 MongoDB allows us to store lists of items natively, so rather than having a
 link table, we can just store a list of tags in each post. So, for both
 efficiency and simplicity's sake, we'll store the tags as strings directly
 within the post, rather than storing references to tags in a separate
 collection. Especially as tags are generally very short (often even shorter
-than a document's id), this denormalization won't impact the size of the
+than a document's id), this denormalisation won't impact very strongly on the
-database very strongly. Let's take a look at the code of our modified
+size of our database. So let's take a look that the code our modified
 :class:`Post` class::
    class Post(Document):
@ -136,24 +121,21 @@ database very strongly. Let's take a look at the code of our modified
        author = ReferenceField(User)
        tags = ListField(StringField(max_length=30))
-The :class:`~mongoengine.fields.ListField` object that is used to define a Post's tags
+The :class:`~mongoengine.ListField` object that is used to define a Post's tags
 takes a field object as its first argument --- this means that you can have
-lists of any type of field (including lists).
+lists of any type of field (including lists). Note that we don't need to
-
+modify the specialised post types as they all inherit from :class:`Post`.
 .. note:: We don't need to modify the specialized post types as they all
    inherit from :class:`Post`.
 Comments
 ^^^^^^^^
 A comment is typically associated with *one* post. In a relational database, to
 display a post with its comments, we would have to retrieve the post from the
-database and then query the database again for the comments associated with the
+database, then query the database again for the comments associated with the
 post. This works, but there is no real reason to be storing the comments
 separately from their associated posts, other than to work around the
 relational model. Using MongoDB we can store the comments as a list of
 *embedded documents* directly on a post document. An embedded document should
-be treated no differently than a regular document; it just doesn't have its own
+be treated no differently that a regular document; it just doesn't have its own
 collection in the database. Using MongoEngine, we can define the structure of
 embedded documents, along with utility methods, in exactly the same way we do
 with regular documents::
@ -173,7 +155,7 @@ We can then store a list of comment documents in our post document::
 Handling deletions of references
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-The :class:`~mongoengine.fields.ReferenceField` object takes a keyword
+The :class:`~mongoengine.ReferenceField` object takes a keyword
 `reverse_delete_rule` for handling deletion rules if the reference is deleted.
 To delete all the posts if a user is deleted set the rule::
@ -183,9 +165,9 @@ To delete all the posts if a user is deleted set the rule::
        tags = ListField(StringField(max_length=30))
        comments = ListField(EmbeddedDocumentField(Comment))
-See :class:`~mongoengine.fields.ReferenceField` for more information.
+See :class:`~mongoengine.ReferenceField` for more information.
-.. note::
+..note::
    MapFields and DictFields currently don't support automatic handling of
    deleted references
@ -196,37 +178,33 @@ Now that we've defined how our documents will be structured, let's start adding
 some documents to the database. Firstly, we'll need to create a :class:`User`
 object::
-    ross = User(email='ross@example.com', first_name='Ross', last_name='Lawley').save()
+    john = User(email='jdoe@example.com', first_name='John', last_name='Doe')
    john.save()
-.. note::
+Note that we could have also defined our user using attribute syntax::
    We could have also defined our user using attribute syntax::
-        ross = User(email='ross@example.com')
+    john = User(email='jdoe@example.com')
-        ross.first_name = 'Ross'
+    john.first_name = 'John'
-        ross.last_name = 'Lawley'
+    john.last_name = 'Doe'
-        ross.save()
+    john.save()
-Assign another user to a variable called ``john``, just like we did above with
+Now that we've got our user in the database, let's add a couple of posts::
 ``ross``.
 Now that we've got our users in the database, let's add a couple of posts::
    post1 = TextPost(title='Fun with MongoEngine', author=john)
    post1.content = 'Took a look at MongoEngine today, looks pretty cool.'
    post1.tags = ['mongodb', 'mongoengine']
    post1.save()
-    post2 = LinkPost(title='MongoEngine Documentation', author=ross)
+    post2 = LinkPost(title='MongoEngine Documentation', author=john)
-    post2.link_url = 'http://docs.mongoengine.com/'
+    post2.link_url = 'http://tractiondigital.com/labs/mongoengine/docs'
    post2.tags = ['mongoengine']
    post2.save()
-.. note:: If you change a field on an object that has already been saved and
+Note that if you change a field on a object that has already been saved, then
-    then call :meth:`save` again, the document will be updated.
+call :meth:`save` again, the document will be updated.
 Accessing our data
 ==================
 So now we've got a couple of posts in our database, how do we display them?
 Each document class (i.e. any class that inherits either directly or indirectly
 from :class:`~mongoengine.Document`) has an :attr:`objects` attribute, which is
@ -234,17 +212,16 @@ used to access the documents in the database collection associated with that
 class. So let's see how we can get our posts' titles::
    for post in Post.objects:
-        print(post.title)
+        print post.title
 Retrieving type-specific information
 ------------------------------------
-
+This will print the titles of our posts, one on each line. But What if we want
 This will print the titles of our posts, one on each line. But what if we want
 to access the type-specific data (link_url, content, etc.)? One way is simply
 to use the :attr:`objects` attribute of a subclass of :class:`Post`::
    for post in TextPost.objects:
-        print(post.content)
+        print post.content
 Using TextPost's :attr:`objects` attribute only returns documents that were
 created using :class:`TextPost`. Actually, there is a more general rule here:
@ -261,21 +238,22 @@ instances of :class:`Post` --- they were instances of the subclass of
 practice::
    for post in Post.objects:
-        print(post.title)
+        print post.title
-        print('=' * len(post.title))
+        print '=' * len(post.title)
        if isinstance(post, TextPost):
-            print(post.content)
+            print post.content
        if isinstance(post, LinkPost):
-            print('Link: {}'.format(post.link_url))
+            print 'Link:', post.link_url
        print
 This would print the title of each post, followed by the content if it was a
 text post, and "Link: <url>" if it was a link post.
 Searching our posts by tag
 --------------------------
 The :attr:`objects` attribute of a :class:`~mongoengine.Document` is actually a
 :class:`~mongoengine.queryset.QuerySet` object. This lazily queries the
 database only when you need the data. It may also be filtered to narrow down
@ -283,7 +261,7 @@ your query.  Let's adjust our query so that only posts with the tag "mongodb"
 are returned::
    for post in Post.objects(tags='mongodb'):
-        print(post.title)
+        print post.title
 There are also methods available on :class:`~mongoengine.queryset.QuerySet`
 objects that allow different results to be returned, for example, calling
@ -292,11 +270,5 @@ the first matched by the query you provide. Aggregation functions may also be
 used on :class:`~mongoengine.queryset.QuerySet` objects::
    num_posts = Post.objects(tags='mongodb').count()
-    print('Found {} posts with tag "mongodb"'.format(num_posts))
+    print 'Found %d posts with tag "mongodb"' % num_posts
 Learning more about MongoEngine
 -------------------------------
 If you got this far you've made a great start, so well done! The next step on
 your MongoEngine journey is the `full user guide <guide/index.html>`_, where
 you can learn in-depth about how to use MongoEngine and MongoDB.
--- a/docs/upgrade.rst
+++ b/docs/upgrade.rst
@ -1,449 +1,12 @@
-#########
+=========
 Upgrading
 #########
 Development
 ***********
 (Fill this out whenever you introduce breaking changes to MongoEngine)
 URLField's constructor no longer takes `verify_exists`
 0.15.0
 ******
 0.14.0
 ******
 This release includes a few bug fixes and a significant code cleanup. The most
 important change is that `QuerySet.as_pymongo` no longer supports a
 `coerce_types` mode. If you used it in the past, a) please let us know of your
 use case, b) you'll need to override `as_pymongo` to get the desired outcome.
 This release also makes the EmbeddedDocument not hashable by default. If you
 use embedded documents in sets or dictionaries, you might have to override
 `__hash__` and implement a hashing logic specific to your use case. See #1528
 for the reason behind this change.
 0.13.0
 ******
 This release adds Unicode support to the `EmailField` and changes its
 structure significantly. Previously, email addresses containing Unicode
 characters didn't work at all. Starting with v0.13.0, domains with Unicode
 characters are supported out of the box, meaning some emails that previously
 didn't pass validation now do. Make sure the rest of your application can
 accept such email addresses. Additionally, if you subclassed the `EmailField`
 in your application and overrode `EmailField.EMAIL_REGEX`, you will have to
 adjust your code to override `EmailField.USER_REGEX`, `EmailField.DOMAIN_REGEX`,
 and potentially `EmailField.UTF8_USER_REGEX`.
 0.12.0
 ******
 This release includes various fixes for the `BaseQuerySet` methods and how they
 are chained together. Since version 0.10.1 applying limit/skip/hint/batch_size
 to an already-existing queryset wouldn't modify the underlying PyMongo cursor.
 This has been fixed now, so you'll need to make sure that your code didn't rely
 on the broken implementation.
 Additionally, a public `BaseQuerySet.clone_into` has been renamed to a private
 `_clone_into`. If you directly used that method in your code, you'll need to
 rename its occurrences.
 0.11.0
 ******
 This release includes a major rehaul of MongoEngine's code quality and
 introduces a few breaking changes. It also touches many different parts of
 the package and although all the changes have been tested and scrutinized,
 you're encouraged to thoroughly test the upgrade.
 First breaking change involves renaming `ConnectionError` to `MongoEngineConnectionError`.
 If you import or catch this exception, you'll need to rename it in your code.
 Second breaking change drops Python v2.6 support. If you run MongoEngine on
 that Python version, you'll need to upgrade it first.
 Third breaking change drops an old backward compatibility measure where
 `from mongoengine.base import ErrorClass` would work on top of
 `from mongoengine.errors import ErrorClass` (where `ErrorClass` is e.g.
 `ValidationError`). If you import any exceptions from `mongoengine.base`,
 change it to `mongoengine.errors`.
 0.10.8
 ******
 This version fixed an issue where specifying a MongoDB URI host would override
 more information than it should. These changes are minor, but they still
 subtly modify the connection logic and thus you're encouraged to test your
 MongoDB connection before shipping v0.10.8 in production.
 0.10.7
 ******
 `QuerySet.aggregate_sum` and `QuerySet.aggregate_average` are dropped. Use
 `QuerySet.sum` and `QuerySet.average` instead which use the aggreation framework
 by default from now on.
 0.9.0
 *****
 The 0.8.7 package on pypi was corrupted.  If upgrading from 0.8.7 to 0.9.0 please follow: ::
    python -m pip uninstall pymongo
    python -m pip uninstall mongoengine
    python -m pip install pymongo==2.8
    python -m pip install mongoengine
 0.8.7
 *****
 Calling reload on deleted / nonexistent documents now raises a DoesNotExist
 exception.
 0.8.2 to 0.8.3
 **************
 Minor change that may impact users:
 DynamicDocument fields are now stored in creation order after any declared
 fields.  Previously they were stored alphabetically.
 0.7 to 0.8
 **********
 There have been numerous backwards breaking changes in 0.8.  The reasons for
 these are to ensure that MongoEngine has sane defaults going forward and that it
 performs the best it can out of the box.  Where possible there have been
 FutureWarnings to help get you ready for the change, but that hasn't been
 possible for the whole of the release.
 .. warning:: Breaking changes - test upgrading on a test system before putting
    live. There maybe multiple manual steps in migrating and these are best honed
    on a staging / test system.
 Python and PyMongo
 ==================
 MongoEngine requires python 2.6 (or above) and pymongo 2.5 (or above)
 Data Model
 ==========
 Inheritance
 -----------
 The inheritance model has changed, we no longer need to store an array of
 :attr:`types` with the model we can just use the classname in :attr:`_cls`.
 This means that you will have to update your indexes for each of your
 inherited classes like so: ::
    # 1. Declaration of the class
    class Animal(Document):
        name = StringField()
        meta = {
            'allow_inheritance': True,
            'indexes': ['name']
        }
    # 2. Remove _types
    collection = Animal._get_collection()
    collection.update({}, {"$unset": {"_types": 1}}, multi=True)
    # 3. Confirm extra data is removed
    count = collection.find({'_types': {"$exists": True}}).count()
    assert count == 0
    # 4. Remove indexes
    info = collection.index_information()
    indexes_to_drop = [key for key, value in info.items()
                       if '_types' in dict(value['key'])]
    for index in indexes_to_drop:
        collection.drop_index(index)
    # 5. Recreate indexes
    Animal.ensure_indexes()
 Document Definition
 -------------------
 The default for inheritance has changed - it is now off by default and
 :attr:`_cls` will not be stored automatically with the class.  So if you extend
 your :class:`~mongoengine.Document` or :class:`~mongoengine.EmbeddedDocuments`
 you will need to declare :attr:`allow_inheritance` in the meta data like so: ::
    class Animal(Document):
        name = StringField()
        meta = {'allow_inheritance': True}
 Previously, if you had data in the database that wasn't defined in the Document
 definition, it would set it as an attribute on the document.  This is no longer
 the case and the data is set only in the ``document._data`` dictionary: ::
    >>> from mongoengine import *
    >>> class Animal(Document):
    ...    name = StringField()
    ...
    >>> cat = Animal(name="kit", size="small")
    # 0.7
    >>> cat.size
    u'small'
    # 0.8
    >>> cat.size
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    AttributeError: 'Animal' object has no attribute 'size'
 The Document class has introduced a reserved function `clean()`, which will be
 called before saving the document. If your document class happens to have a method
 with the same name, please try to rename it.
    def clean(self):
        pass
 ReferenceField
 --------------
 ReferenceFields now store ObjectIds by default - this is more efficient than
 DBRefs as we already know what Document types they reference::
    # Old code
    class Animal(Document):
        name = ReferenceField('self')
    # New code to keep dbrefs
    class Animal(Document):
        name = ReferenceField('self', dbref=True)
 To migrate all the references you need to touch each object and mark it as dirty
 eg::
    # Doc definition
    class Person(Document):
        name = StringField()
        parent = ReferenceField('self')
        friends = ListField(ReferenceField('self'))
    # Mark all ReferenceFields as dirty and save
    for p in Person.objects:
        p._mark_as_changed('parent')
        p._mark_as_changed('friends')
        p.save()
 `An example test migration for ReferenceFields is available on github
 <https://github.com/MongoEngine/mongoengine/blob/master/tests/migration/refrencefield_dbref_to_object_id.py>`_.
 .. Note:: Internally mongoengine handles ReferenceFields the same, so they are
   converted to DBRef on loading and ObjectIds or DBRefs depending on settings
   on storage.
 UUIDField
 ---------
 UUIDFields now default to storing binary values::
    # Old code
    class Animal(Document):
        uuid = UUIDField()
    # New code
    class Animal(Document):
        uuid = UUIDField(binary=False)
 To migrate all the uuids you need to touch each object and mark it as dirty
 eg::
    # Doc definition
    class Animal(Document):
        uuid = UUIDField()
    # Mark all UUIDFields as dirty and save
    for a in Animal.objects:
        a._mark_as_changed('uuid')
        a.save()
 `An example test migration for UUIDFields is available on github
 <https://github.com/MongoEngine/mongoengine/blob/master/tests/migration/uuidfield_to_binary.py>`_.
 DecimalField
 ------------
 DecimalFields now store floats - previously it was storing strings and that
 made it impossible to do comparisons when querying correctly.::
    # Old code
    class Person(Document):
        balance = DecimalField()
    # New code
    class Person(Document):
        balance = DecimalField(force_string=True)
 To migrate all the DecimalFields you need to touch each object and mark it as dirty
 eg::
    # Doc definition
    class Person(Document):
        balance = DecimalField()
    # Mark all DecimalField's as dirty and save
    for p in Person.objects:
        p._mark_as_changed('balance')
        p.save()
 .. note:: DecimalFields have also been improved with the addition of precision
    and rounding.  See :class:`~mongoengine.fields.DecimalField` for more information.
 `An example test migration for DecimalFields is available on github
 <https://github.com/MongoEngine/mongoengine/blob/master/tests/migration/decimalfield_as_float.py>`_.
 Cascading Saves
 ---------------
 To improve performance document saves will no longer automatically cascade.
 Any changes to a Document's references will either have to be saved manually or
 you will have to explicitly tell it to cascade on save::
    # At the class level:
    class Person(Document):
        meta = {'cascade': True}
    # Or on save:
    my_document.save(cascade=True)
 Storage
 -------
 Document and Embedded Documents are now serialized based on declared field order.
 Previously, the data was passed to mongodb as a dictionary and which meant that
 order wasn't guaranteed - so things like ``$addToSet`` operations on
 :class:`~mongoengine.EmbeddedDocument` could potentially fail in unexpected
 ways.
 If this impacts you, you may want to rewrite the objects using the
 ``doc.mark_as_dirty('field')`` pattern described above.  If you are using a
 compound primary key then you will need to ensure the order is fixed and match
 your EmbeddedDocument to that order.
 Querysets
 =========
 Attack of the clones
 --------------------
 Querysets now return clones and should no longer be considered editable in
 place.  This brings us in line with how Django's querysets work and removes a
 long running gotcha.  If you edit your querysets inplace you will have to
 update your code like so: ::
    # Old code:
    mammals = Animal.objects(type="mammal")
    mammals.filter(order="Carnivora")       # Returns a cloned queryset that isn't assigned to anything - so this will break in 0.8
    [m for m in mammals]                    # This will return all mammals in 0.8 as the 2nd filter returned a new queryset
    # Update example a) assign queryset after a change:
    mammals = Animal.objects(type="mammal")
    carnivores = mammals.filter(order="Carnivora") # Reassign the new queryset so filter can be applied
    [m for m in carnivores]                        # This will return all carnivores
    # Update example b) chain the queryset:
    mammals = Animal.objects(type="mammal").filter(order="Carnivora")  # The final queryset is assgined to mammals
    [m for m in mammals]                                               # This will return all carnivores
 Len iterates the queryset
 -------------------------
 If you ever did `len(queryset)` it previously did a `count()` under the covers,
 this caused some unusual issues.  As `len(queryset)` is most often used by
 `list(queryset)` we now cache the queryset results and use that for the length.
 This isn't as performant as a `count()` and if you aren't iterating the
 queryset you should upgrade to use count::
    # Old code
    len(Animal.objects(type="mammal"))
    # New code
    Animal.objects(type="mammal").count()
 .only() now inline with .exclude()
 ----------------------------------
 The behaviour of `.only()` was highly ambiguous, now it works in mirror fashion
 to `.exclude()`.  Chaining `.only()` calls will increase the fields required::
    # Old code
    Animal.objects().only(['type', 'name']).only('name', 'order')  # Would have returned just `name`
    # New code
    Animal.objects().only('name')
    # Note:
    Animal.objects().only(['name']).only('order')  # Now returns `name` *and* `order`
 Client
 ======
 PyMongo 2.4 came with a new connection client; MongoClient_ and started the
 depreciation of the old :class:`~pymongo.connection.Connection`. MongoEngine
 now uses the latest `MongoClient` for connections.  By default operations were
 `safe` but if you turned them off or used the connection directly this will
 impact your queries.
 Querysets
 ---------
 Safe
 ^^^^
 `safe` has been depreciated in the new MongoClient connection.  Please use
 `write_concern` instead.  As `safe` always defaulted as `True` normally no code
 change is required. To disable confirmation of the write just pass `{"w": 0}`
 eg: ::
   # Old
   Animal(name="Dinasour").save(safe=False)
   # new code:
   Animal(name="Dinasour").save(write_concern={"w": 0})
 Write Concern
 ^^^^^^^^^^^^^
 `write_options` has been replaced with `write_concern` to bring it inline with
 pymongo. To upgrade simply rename any instances where you used the `write_option`
 keyword  to `write_concern` like so::
   # Old code:
   Animal(name="Dinasour").save(write_options={"w": 2})
   # new code:
   Animal(name="Dinasour").save(write_concern={"w": 2})
 Indexes
 =======
 Index methods are no longer tied to querysets but rather to the document class.
 Although `QuerySet._ensure_indexes` and `QuerySet.ensure_index` still exist.
 They should be replaced with :func:`~mongoengine.Document.ensure_indexes` /
 :func:`~mongoengine.Document.ensure_index`.
 SequenceFields
 ==============
 :class:`~mongoengine.fields.SequenceField` now inherits from `BaseField` to
 allow flexible storage of the calculated value.  As such MIN and MAX settings
 are no longer handled.
 .. _MongoClient: http://blog.mongodb.org/post/36666163412/introducing-mongoclient
 0.6 to 0.7
-**********
+==========
 Cascade saves
-=============
+-------------
 Saves will raise a `FutureWarning` if they cascade and cascade hasn't been set
 to True.  This is because in 0.8 it will default to False.  If you require
@ -457,11 +20,11 @@ via `save` eg ::
    # Or in code:
    my_document.save(cascade=True)
-.. note::
+.. note ::
    Remember: cascading saves **do not** cascade through lists.
 ReferenceFields
-===============
+---------------
 ReferenceFields now can store references as ObjectId strings instead of DBRefs.
 This will become the default in 0.8 and if `dbref` is not set a `FutureWarning`
@ -490,7 +53,7 @@ migrate ::
 item_frequencies
-================
+----------------
 In the 0.6 series we added support for null / zero / false values in
 item_frequencies.  A side effect was to return keys in the value they are
@ -498,15 +61,8 @@ stored in rather than as string representations.  Your code may need to be
 updated to handle native types rather than strings keys for the results of
 item frequency queries.
 BinaryFields
 ============
 Binary fields have been updated so that they are native binary types.  If you
 previously were doing `str` comparisons with binary field values you will have
 to update and wrap the value in a `str`.
 0.5 to 0.6
-**********
+==========
 Embedded Documents - if you had a `pk` field you will have to rename it from
 `_id` to `pk` as pk is no longer a property of Embedded Documents.
@ -521,26 +77,26 @@ Document.objects.with_id - now raises an InvalidQueryError if used with a
 filter.
 FutureWarning - A future warning has been added to all inherited classes that
-don't define :attr:`allow_inheritance` in their meta.
+don't define `allow_inheritance` in their meta.
 You may need to update pyMongo to 2.0 for use with Sharding.
 0.4 to 0.5
-**********
+===========
 There have been the following backwards incompatibilities from 0.4 to 0.5.  The
 main areas of changed are: choices in fields, map_reduce and collection names.
 Choice options:
-===============
+---------------
-Are now expected to be an iterable of tuples, with the first element in each
+Are now expected to be an iterable of tuples, with  the first element in each
 tuple being the actual value to be stored. The second element is the
 human-readable name for the option.
 PyMongo / MongoDB
-=================
+-----------------
 map reduce now requires pymongo 1.11+- The pymongo `merge_output` and
 `reduce_output` parameters, have been depreciated.
@ -554,10 +110,10 @@ such the following have been changed:
 Default collection naming
-=========================
+-------------------------
-Previously it was just lowercase, it's now much more pythonic and readable as
+Previously it was just lowercase, its now much more pythonic and readable as
-it's lowercase and underscores, previously ::
+its lowercase and underscores, previously ::
    class MyAceDocument(Document):
        pass
@ -620,9 +176,3 @@ Alternatively, you can rename your collections eg ::
        else:
            print "Upgraded collection names"
 mongodb 1.8 > 2.0 +
 ===================
 It's been reported that indexes may need to be recreated to the newer version of indexes.
 To do this drop indexes and call ``ensure_indexes`` on each model.
--- a/mongoengine/init.py
+++ b/mongoengine/init.py
@ -1,43 +1,23 @@
-# Import submodules so that we can expose their __all__
+import document
-from mongoengine import (
+from document import *
-    connection,
+import fields
-    document,
+from fields import *
-    errors,
+import connection
-    fields,
+from connection import *
-    queryset,
+import queryset
-    signals,
+from queryset import *
-)
+import signals
 from signals import *
-# Import everything from each submodule so that it can be accessed via
+__all__ = (document.__all__ + fields.__all__ + connection.__all__ +
-# mongoengine, e.g. instead of `from mongoengine.connection import connect`,
+           queryset.__all__ + signals.__all__)
 # users can simply use `from mongoengine import connect`, or even
 # `from mongoengine import *` and then `connect('testdb')`.
 from mongoengine.connection import *  # noqa: F401
 from mongoengine.document import *  # noqa: F401
 from mongoengine.errors import *  # noqa: F401
 from mongoengine.fields import *  # noqa: F401
 from mongoengine.queryset import *  # noqa: F401
 from mongoengine.signals import *  # noqa: F401
-__all__ = (
+VERSION = (0, '7rc1')
    list(document.__all__)
    + list(fields.__all__)
    + list(connection.__all__)
    + list(queryset.__all__)
    + list(signals.__all__)
    + list(errors.__all__)
 )
 VERSION = (0, 23, 1)
 def get_version():
-    """Return the VERSION as a string.
+    if isinstance(VERSION[-1], basestring):
-
+        return '.'.join(map(str, VERSION[:-1])) + VERSION[-1]
-    For example, if `VERSION == (0, 10, 7)`, return '0.10.7'.
+    return '.'.join(map(str, VERSION))
    """
    return ".".join(map(str, VERSION))
 __version__ = get_version()
--- a/mongoengine/base.py
+++ b/mongoengine/base.py
--- a/mongoengine/base/init.py
+++ b/mongoengine/base/init.py
@ -1,33 +0,0 @@
 # Base module is split into several files for convenience. Files inside of
 # this module should import from a specific submodule (e.g.
 # `from mongoengine.base.document import BaseDocument`), but all of the
 # other modules should import directly from the top-level module (e.g.
 # `from mongoengine.base import BaseDocument`). This approach is cleaner and
 # also helps with cyclical import errors.
 from mongoengine.base.common import *
 from mongoengine.base.datastructures import *
 from mongoengine.base.document import *
 from mongoengine.base.fields import *
 from mongoengine.base.metaclasses import *
 __all__ = (
    # common
    "UPDATE_OPERATORS",
    "_document_registry",
    "get_document",
    # datastructures
    "BaseDict",
    "BaseList",
    "EmbeddedDocumentList",
    "LazyReference",
    # document
    "BaseDocument",
    # fields
    "BaseField",
    "ComplexBaseField",
    "ObjectIdField",
    "GeoJsonBaseField",
    # metaclasses
    "DocumentMetaclass",
    "TopLevelDocumentMetaclass",
 )
--- a/mongoengine/base/common.py
+++ b/mongoengine/base/common.py
@ -1,62 +0,0 @@
 from mongoengine.errors import NotRegistered
 __all__ = ("UPDATE_OPERATORS", "get_document", "_document_registry")
 UPDATE_OPERATORS = {
    "set",
    "unset",
    "inc",
    "dec",
    "mul",
    "pop",
    "push",
    "push_all",
    "pull",
    "pull_all",
    "add_to_set",
    "set_on_insert",
    "min",
    "max",
    "rename",
 }
 _document_registry = {}
 def get_document(name):
    """Get a registered Document class by name."""
    doc = _document_registry.get(name, None)
    if not doc:
        # Possible old style name
        single_end = name.split(".")[-1]
        compound_end = ".%s" % single_end
        possible_match = [
            k for k in _document_registry if k.endswith(compound_end) or k == single_end
        ]
        if len(possible_match) == 1:
            doc = _document_registry.get(possible_match.pop(), None)
    if not doc:
        raise NotRegistered(
            """
            `%s` has not been registered in the document registry.
            Importing the document class automatically registers it, has it
            been imported?
        """.strip()
            % name
        )
    return doc
 def _get_documents_by_db(connection_alias, default_connection_alias):
    """Get all registered Documents class attached to a given database"""
    def get_doc_alias(doc_cls):
        return doc_cls._meta.get("db_alias", default_connection_alias)
    return [
        doc_cls
        for doc_cls in _document_registry.values()
        if get_doc_alias(doc_cls) == connection_alias
    ]
--- a/mongoengine/base/datastructures.py
+++ b/mongoengine/base/datastructures.py
@ -1,473 +0,0 @@
 import weakref
 from bson import DBRef
 from mongoengine.common import _import_class
 from mongoengine.errors import DoesNotExist, MultipleObjectsReturned
 __all__ = (
    "BaseDict",
    "StrictDict",
    "BaseList",
    "EmbeddedDocumentList",
    "LazyReference",
 )
 def mark_as_changed_wrapper(parent_method):
    """Decorator that ensures _mark_as_changed method gets called."""
    def wrapper(self, *args, **kwargs):
        # Can't use super() in the decorator.
        result = parent_method(self, *args, **kwargs)
        self._mark_as_changed()
        return result
    return wrapper
 def mark_key_as_changed_wrapper(parent_method):
    """Decorator that ensures _mark_as_changed method gets called with the key argument"""
    def wrapper(self, key, *args, **kwargs):
        # Can't use super() in the decorator.
        result = parent_method(self, key, *args, **kwargs)
        self._mark_as_changed(key)
        return result
    return wrapper
 class BaseDict(dict):
    """A special dict so we can watch any changes."""
    _dereferenced = False
    _instance = None
    _name = None
    def __init__(self, dict_items, instance, name):
        BaseDocument = _import_class("BaseDocument")
        if isinstance(instance, BaseDocument):
            self._instance = weakref.proxy(instance)
        self._name = name
        super().__init__(dict_items)
    def get(self, key, default=None):
        # get does not use __getitem__ by default so we must override it as well
        try:
            return self.__getitem__(key)
        except KeyError:
            return default
    def __getitem__(self, key):
        value = super().__getitem__(key)
        EmbeddedDocument = _import_class("EmbeddedDocument")
        if isinstance(value, EmbeddedDocument) and value._instance is None:
            value._instance = self._instance
        elif isinstance(value, dict) and not isinstance(value, BaseDict):
            value = BaseDict(value, None, f"{self._name}.{key}")
            super().__setitem__(key, value)
            value._instance = self._instance
        elif isinstance(value, list) and not isinstance(value, BaseList):
            value = BaseList(value, None, f"{self._name}.{key}")
            super().__setitem__(key, value)
            value._instance = self._instance
        return value
    def __getstate__(self):
        self.instance = None
        self._dereferenced = False
        return self
    def __setstate__(self, state):
        self = state
        return self
    __setitem__ = mark_key_as_changed_wrapper(dict.__setitem__)
    __delattr__ = mark_key_as_changed_wrapper(dict.__delattr__)
    __delitem__ = mark_key_as_changed_wrapper(dict.__delitem__)
    pop = mark_as_changed_wrapper(dict.pop)
    clear = mark_as_changed_wrapper(dict.clear)
    update = mark_as_changed_wrapper(dict.update)
    popitem = mark_as_changed_wrapper(dict.popitem)
    setdefault = mark_as_changed_wrapper(dict.setdefault)
    def _mark_as_changed(self, key=None):
        if hasattr(self._instance, "_mark_as_changed"):
            if key:
                self._instance._mark_as_changed(f"{self._name}.{key}")
            else:
                self._instance._mark_as_changed(self._name)
 class BaseList(list):
    """A special list so we can watch any changes."""
    _dereferenced = False
    _instance = None
    _name = None
    def __init__(self, list_items, instance, name):
        BaseDocument = _import_class("BaseDocument")
        if isinstance(instance, BaseDocument):
            self._instance = weakref.proxy(instance)
        self._name = name
        super().__init__(list_items)
    def __getitem__(self, key):
        # change index to positive value because MongoDB does not support negative one
        if isinstance(key, int) and key < 0:
            key = len(self) + key
        value = super().__getitem__(key)
        if isinstance(key, slice):
            # When receiving a slice operator, we don't convert the structure and bind
            # to parent's instance. This is buggy for now but would require more work to be handled properly
            return value
        EmbeddedDocument = _import_class("EmbeddedDocument")
        if isinstance(value, EmbeddedDocument) and value._instance is None:
            value._instance = self._instance
        elif isinstance(value, dict) and not isinstance(value, BaseDict):
            # Replace dict by BaseDict
            value = BaseDict(value, None, f"{self._name}.{key}")
            super().__setitem__(key, value)
            value._instance = self._instance
        elif isinstance(value, list) and not isinstance(value, BaseList):
            # Replace list by BaseList
            value = BaseList(value, None, f"{self._name}.{key}")
            super().__setitem__(key, value)
            value._instance = self._instance
        return value
    def __iter__(self):
        yield from super().__iter__()
    def __getstate__(self):
        self.instance = None
        self._dereferenced = False
        return self
    def __setstate__(self, state):
        self = state
        return self
    def __setitem__(self, key, value):
        changed_key = key
        if isinstance(key, slice):
            # In case of slice, we don't bother to identify the exact elements being updated
            # instead, we simply marks the whole list as changed
            changed_key = None
        result = super().__setitem__(key, value)
        self._mark_as_changed(changed_key)
        return result
    append = mark_as_changed_wrapper(list.append)
    extend = mark_as_changed_wrapper(list.extend)
    insert = mark_as_changed_wrapper(list.insert)
    pop = mark_as_changed_wrapper(list.pop)
    remove = mark_as_changed_wrapper(list.remove)
    reverse = mark_as_changed_wrapper(list.reverse)
    sort = mark_as_changed_wrapper(list.sort)
    __delitem__ = mark_as_changed_wrapper(list.__delitem__)
    __iadd__ = mark_as_changed_wrapper(list.__iadd__)
    __imul__ = mark_as_changed_wrapper(list.__imul__)
    def _mark_as_changed(self, key=None):
        if hasattr(self._instance, "_mark_as_changed"):
            if key is not None:
                self._instance._mark_as_changed(f"{self._name}.{key % len(self)}")
            else:
                self._instance._mark_as_changed(self._name)
 class EmbeddedDocumentList(BaseList):
    def __init__(self, list_items, instance, name):
        super().__init__(list_items, instance, name)
        self._instance = instance
    @classmethod
    def __match_all(cls, embedded_doc, kwargs):
        """Return True if a given embedded doc matches all the filter
        kwargs. If it doesn't return False.
        """
        for key, expected_value in kwargs.items():
            doc_val = getattr(embedded_doc, key)
            if doc_val != expected_value and str(doc_val) != expected_value:
                return False
        return True
    @classmethod
    def __only_matches(cls, embedded_docs, kwargs):
        """Return embedded docs that match the filter kwargs."""
        if not kwargs:
            return embedded_docs
        return [doc for doc in embedded_docs if cls.__match_all(doc, kwargs)]
    def filter(self, **kwargs):
        """
        Filters the list by only including embedded documents with the
        given keyword arguments.
        This method only supports simple comparison (e.g. .filter(name='John Doe'))
        and does not support operators like __gte, __lte, __icontains like queryset.filter does
        :param kwargs: The keyword arguments corresponding to the fields to
         filter on. *Multiple arguments are treated as if they are ANDed
         together.*
        :return: A new ``EmbeddedDocumentList`` containing the matching
         embedded documents.
        Raises ``AttributeError`` if a given keyword is not a valid field for
        the embedded document class.
        """
        values = self.__only_matches(self, kwargs)
        return EmbeddedDocumentList(values, self._instance, self._name)
    def exclude(self, **kwargs):
        """
        Filters the list by excluding embedded documents with the given
        keyword arguments.
        :param kwargs: The keyword arguments corresponding to the fields to
         exclude on. *Multiple arguments are treated as if they are ANDed
         together.*
        :return: A new ``EmbeddedDocumentList`` containing the non-matching
         embedded documents.
        Raises ``AttributeError`` if a given keyword is not a valid field for
        the embedded document class.
        """
        exclude = self.__only_matches(self, kwargs)
        values = [item for item in self if item not in exclude]
        return EmbeddedDocumentList(values, self._instance, self._name)
    def count(self):
        """
        The number of embedded documents in the list.
        :return: The length of the list, equivalent to the result of ``len()``.
        """
        return len(self)
    def get(self, **kwargs):
        """
        Retrieves an embedded document determined by the given keyword
        arguments.
        :param kwargs: The keyword arguments corresponding to the fields to
         search on. *Multiple arguments are treated as if they are ANDed
         together.*
        :return: The embedded document matched by the given keyword arguments.
        Raises ``DoesNotExist`` if the arguments used to query an embedded
        document returns no results. ``MultipleObjectsReturned`` if more
        than one result is returned.
        """
        values = self.__only_matches(self, kwargs)
        if len(values) == 0:
            raise DoesNotExist("%s matching query does not exist." % self._name)
        elif len(values) > 1:
            raise MultipleObjectsReturned(
                "%d items returned, instead of 1" % len(values)
            )
        return values[0]
    def first(self):
        """Return the first embedded document in the list, or ``None``
        if empty.
        """
        if len(self) > 0:
            return self[0]
    def create(self, **values):
        """
        Creates a new instance of the EmbeddedDocument and appends it to this EmbeddedDocumentList.
        .. note::
            the instance of the EmbeddedDocument is not automatically saved to the database.
            You still need to call .save() on the parent Document.
        :param values: A dictionary of values for the embedded document.
        :return: The new embedded document instance.
        """
        name = self._name
        EmbeddedClass = self._instance._fields[name].field.document_type_obj
        self._instance[self._name].append(EmbeddedClass(**values))
        return self._instance[self._name][-1]
    def save(self, *args, **kwargs):
        """
        Saves the ancestor document.
        :param args: Arguments passed up to the ancestor Document's save
         method.
        :param kwargs: Keyword arguments passed up to the ancestor Document's
         save method.
        """
        self._instance.save(*args, **kwargs)
    def delete(self):
        """
        Deletes the embedded documents from the database.
        .. note::
            The embedded document changes are not automatically saved
            to the database after calling this method.
        :return: The number of entries deleted.
        """
        values = list(self)
        for item in values:
            self._instance[self._name].remove(item)
        return len(values)
    def update(self, **update):
        """
        Updates the embedded documents with the given replacement values. This
        function does not support mongoDB update operators such as ``inc__``.
        .. note::
            The embedded document changes are not automatically saved
            to the database after calling this method.
        :param update: A dictionary of update values to apply to each
         embedded document.
        :return: The number of entries updated.
        """
        if len(update) == 0:
            return 0
        values = list(self)
        for item in values:
            for k, v in update.items():
                setattr(item, k, v)
        return len(values)
 class StrictDict:
    __slots__ = ()
    _special_fields = {"get", "pop", "iteritems", "items", "keys", "create"}
    _classes = {}
    def __init__(self, **kwargs):
        for k, v in kwargs.items():
            setattr(self, k, v)
    def __getitem__(self, key):
        key = "_reserved_" + key if key in self._special_fields else key
        try:
            return getattr(self, key)
        except AttributeError:
            raise KeyError(key)
    def __setitem__(self, key, value):
        key = "_reserved_" + key if key in self._special_fields else key
        return setattr(self, key, value)
    def __contains__(self, key):
        return hasattr(self, key)
    def get(self, key, default=None):
        try:
            return self[key]
        except KeyError:
            return default
    def pop(self, key, default=None):
        v = self.get(key, default)
        try:
            delattr(self, key)
        except AttributeError:
            pass
        return v
    def iteritems(self):
        for key in self:
            yield key, self[key]
    def items(self):
        return [(k, self[k]) for k in iter(self)]
    def iterkeys(self):
        return iter(self)
    def keys(self):
        return list(iter(self))
    def __iter__(self):
        return (key for key in self.__slots__ if hasattr(self, key))
    def __len__(self):
        return len(list(self.items()))
    def __eq__(self, other):
        return list(self.items()) == list(other.items())
    def __ne__(self, other):
        return not (self == other)
    @classmethod
    def create(cls, allowed_keys):
        allowed_keys_tuple = tuple(
            ("_reserved_" + k if k in cls._special_fields else k) for k in allowed_keys
        )
        allowed_keys = frozenset(allowed_keys_tuple)
        if allowed_keys not in cls._classes:
            class SpecificStrictDict(cls):
                __slots__ = allowed_keys_tuple
                def __repr__(self):
                    return "{%s}" % ", ".join(
                        f'"{k!s}": {v!r}' for k, v in self.items()
                    )
            cls._classes[allowed_keys] = SpecificStrictDict
        return cls._classes[allowed_keys]
 class LazyReference(DBRef):
    __slots__ = ("_cached_doc", "passthrough", "document_type")
    def fetch(self, force=False):
        if not self._cached_doc or force:
            self._cached_doc = self.document_type.objects.get(pk=self.pk)
            if not self._cached_doc:
                raise DoesNotExist("Trying to dereference unknown document %s" % (self))
        return self._cached_doc
    @property
    def pk(self):
        return self.id
    def __init__(self, document_type, pk, cached_doc=None, passthrough=False):
        self.document_type = document_type
        self._cached_doc = cached_doc
        self.passthrough = passthrough
        super().__init__(self.document_type._get_collection_name(), pk)
    def __getitem__(self, name):
        if not self.passthrough:
            raise KeyError()
        document = self.fetch()
        return document[name]
    def __getattr__(self, name):
        if not object.__getattribute__(self, "passthrough"):
            raise AttributeError()
        document = self.fetch()
        try:
            return document[name]
        except KeyError:
            raise AttributeError()
    def __repr__(self):
        return f"<LazyReference({self.document_type}, {self.pk!r})>"
--- a/mongoengine/base/document.py
+++ b/mongoengine/base/document.py
--- a/mongoengine/base/fields.py
+++ b/mongoengine/base/fields.py
@ -1,686 +0,0 @@
 import operator
 import weakref
 import pymongo
 from bson import SON, DBRef, ObjectId
 from mongoengine.base.common import UPDATE_OPERATORS
 from mongoengine.base.datastructures import (
    BaseDict,
    BaseList,
    EmbeddedDocumentList,
 )
 from mongoengine.common import _import_class
 from mongoengine.errors import DeprecatedError, ValidationError
 __all__ = ("BaseField", "ComplexBaseField", "ObjectIdField", "GeoJsonBaseField")
 class BaseField:
    """A base class for fields in a MongoDB document. Instances of this class
    may be added to subclasses of `Document` to define a document's schema.
    """
    name = None  # set in TopLevelDocumentMetaclass
    _geo_index = False
    _auto_gen = False  # Call `generate` to generate a value
    _auto_dereference = True
    # These track each time a Field instance is created. Used to retain order.
    # The auto_creation_counter is used for fields that MongoEngine implicitly
    # creates, creation_counter is used for all user-specified fields.
    creation_counter = 0
    auto_creation_counter = -1
    def __init__(
        self,
        db_field=None,
        required=False,
        default=None,
        unique=False,
        unique_with=None,
        primary_key=False,
        validation=None,
        choices=None,
        null=False,
        sparse=False,
        **kwargs,
    ):
        """
        :param db_field: The database field to store this field in
            (defaults to the name of the field)
        :param required: If the field is required. Whether it has to have a
            value or not. Defaults to False.
        :param default: (optional) The default value for this field if no value
            has been set (or if the value has been unset).  It can be a
            callable.
        :param unique: Is the field value unique or not.  Defaults to False.
        :param unique_with: (optional) The other field this field should be
            unique with.
        :param primary_key: Mark this field as the primary key. Defaults to False.
        :param validation: (optional) A callable to validate the value of the
            field.  The callable takes the value as parameter and should raise
            a ValidationError if validation fails
        :param choices: (optional) The valid choices
        :param null: (optional) If the field value can be null. If no and there is a default value
            then the default value is set
        :param sparse: (optional) `sparse=True` combined with `unique=True` and `required=False`
            means that uniqueness won't be enforced for `None` values
        :param **kwargs: (optional) Arbitrary indirection-free metadata for
            this field can be supplied as additional keyword arguments and
            accessed as attributes of the field. Must not conflict with any
            existing attributes. Common metadata includes `verbose_name` and
            `help_text`.
        """
        self.db_field = db_field if not primary_key else "_id"
        self.required = required or primary_key
        self.default = default
        self.unique = bool(unique or unique_with)
        self.unique_with = unique_with
        self.primary_key = primary_key
        self.validation = validation
        self.choices = choices
        self.null = null
        self.sparse = sparse
        self._owner_document = None
        # Make sure db_field is a string (if it's explicitly defined).
        if self.db_field is not None and not isinstance(self.db_field, str):
            raise TypeError("db_field should be a string.")
        # Make sure db_field doesn't contain any forbidden characters.
        if isinstance(self.db_field, str) and (
            "." in self.db_field
            or "\0" in self.db_field
            or self.db_field.startswith("$")
        ):
            raise ValueError(
                'field names cannot contain dots (".") or null characters '
                '("\\0"), and they must not start with a dollar sign ("$").'
            )
        # Detect and report conflicts between metadata and base properties.
        conflicts = set(dir(self)) & set(kwargs)
        if conflicts:
            raise TypeError(
                "%s already has attribute(s): %s"
                % (self.__class__.__name__, ", ".join(conflicts))
            )
        # Assign metadata to the instance
        # This efficient method is available because no __slots__ are defined.
        self.__dict__.update(kwargs)
        # Adjust the appropriate creation counter, and save our local copy.
        if self.db_field == "_id":
            self.creation_counter = BaseField.auto_creation_counter
            BaseField.auto_creation_counter -= 1
        else:
            self.creation_counter = BaseField.creation_counter
            BaseField.creation_counter += 1
    def __get__(self, instance, owner):
        """Descriptor for retrieving a value from a field in a document."""
        if instance is None:
            # Document class being used rather than a document object
            return self
        # Get value from document instance if available
        return instance._data.get(self.name)
    def __set__(self, instance, value):
        """Descriptor for assigning a value to a field in a document."""
        # If setting to None and there is a default value provided for this
        # field, then set the value to the default value.
        if value is None:
            if self.null:
                value = None
            elif self.default is not None:
                value = self.default
                if callable(value):
                    value = value()
        if instance._initialised:
            try:
                value_has_changed = (
                    self.name not in instance._data
                    or instance._data[self.name] != value
                )
                if value_has_changed:
                    instance._mark_as_changed(self.name)
            except Exception:
                # Some values can't be compared and throw an error when we
                # attempt to do so (e.g. tz-naive and tz-aware datetimes).
                # Mark the field as changed in such cases.
                instance._mark_as_changed(self.name)
        EmbeddedDocument = _import_class("EmbeddedDocument")
        if isinstance(value, EmbeddedDocument):
            value._instance = weakref.proxy(instance)
        elif isinstance(value, (list, tuple)):
            for v in value:
                if isinstance(v, EmbeddedDocument):
                    v._instance = weakref.proxy(instance)
        instance._data[self.name] = value
    def error(self, message="", errors=None, field_name=None):
        """Raise a ValidationError."""
        field_name = field_name if field_name else self.name
        raise ValidationError(message, errors=errors, field_name=field_name)
    def to_python(self, value):
        """Convert a MongoDB-compatible type to a Python type."""
        return value
    def to_mongo(self, value):
        """Convert a Python type to a MongoDB-compatible type."""
        return self.to_python(value)
    def _to_mongo_safe_call(self, value, use_db_field=True, fields=None):
        """Helper method to call to_mongo with proper inputs."""
        f_inputs = self.to_mongo.__code__.co_varnames
        ex_vars = {}
        if "fields" in f_inputs:
            ex_vars["fields"] = fields
        if "use_db_field" in f_inputs:
            ex_vars["use_db_field"] = use_db_field
        return self.to_mongo(value, **ex_vars)
    def prepare_query_value(self, op, value):
        """Prepare a value that is being used in a query for PyMongo."""
        if op in UPDATE_OPERATORS:
            self.validate(value)
        return value
    def validate(self, value, clean=True):
        """Perform validation on a value."""
        pass
    def _validate_choices(self, value):
        Document = _import_class("Document")
        EmbeddedDocument = _import_class("EmbeddedDocument")
        choice_list = self.choices
        if isinstance(next(iter(choice_list)), (list, tuple)):
            # next(iter) is useful for sets
            choice_list = [k for k, _ in choice_list]
        # Choices which are other types of Documents
        if isinstance(value, (Document, EmbeddedDocument)):
            if not any(isinstance(value, c) for c in choice_list):
                self.error("Value must be an instance of %s" % (choice_list))
        # Choices which are types other than Documents
        else:
            values = value if isinstance(value, (list, tuple)) else [value]
            if len(set(values) - set(choice_list)):
                self.error("Value must be one of %s" % str(choice_list))
    def _validate(self, value, **kwargs):
        # Check the Choices Constraint
        if self.choices:
            self._validate_choices(value)
        # check validation argument
        if self.validation is not None:
            if callable(self.validation):
                try:
                    # breaking change of 0.18
                    # Get rid of True/False-type return for the validation method
                    # in favor of having validation raising a ValidationError
                    ret = self.validation(value)
                    if ret is not None:
                        raise DeprecatedError(
                            "validation argument for `%s` must not return anything, "
                            "it should raise a ValidationError if validation fails"
                            % self.name
                        )
                except ValidationError as ex:
                    self.error(str(ex))
            else:
                raise ValueError(
                    'validation argument for `"%s"` must be a ' "callable." % self.name
                )
        self.validate(value, **kwargs)
    @property
    def owner_document(self):
        return self._owner_document
    def _set_owner_document(self, owner_document):
        self._owner_document = owner_document
    @owner_document.setter
    def owner_document(self, owner_document):
        self._set_owner_document(owner_document)
 class ComplexBaseField(BaseField):
    """Handles complex fields, such as lists / dictionaries.
    Allows for nesting of embedded documents inside complex types.
    Handles the lazy dereferencing of a queryset by lazily dereferencing all
    items in a list / dict rather than one at a time.
    """
    def __init__(self, field=None, **kwargs):
        self.field = field
        super().__init__(**kwargs)
    @staticmethod
    def _lazy_load_refs(instance, name, ref_values, *, max_depth):
        _dereference = _import_class("DeReference")()
        documents = _dereference(
            ref_values,
            max_depth=max_depth,
            instance=instance,
            name=name,
        )
        return documents
    def __get__(self, instance, owner):
        """Descriptor to automatically dereference references."""
        if instance is None:
            # Document class being used rather than a document object
            return self
        ReferenceField = _import_class("ReferenceField")
        GenericReferenceField = _import_class("GenericReferenceField")
        EmbeddedDocumentListField = _import_class("EmbeddedDocumentListField")
        auto_dereference = instance._fields[self.name]._auto_dereference
        dereference = auto_dereference and (
            self.field is None
            or isinstance(self.field, (GenericReferenceField, ReferenceField))
        )
        if (
            instance._initialised
            and dereference
            and instance._data.get(self.name)
            and not getattr(instance._data[self.name], "_dereferenced", False)
        ):
            ref_values = instance._data.get(self.name)
            instance._data[self.name] = self._lazy_load_refs(
                ref_values=ref_values, instance=instance, name=self.name, max_depth=1
            )
            if hasattr(instance._data[self.name], "_dereferenced"):
                instance._data[self.name]._dereferenced = True
        value = super().__get__(instance, owner)
        # Convert lists / values so we can watch for any changes on them
        if isinstance(value, (list, tuple)):
            if issubclass(type(self), EmbeddedDocumentListField) and not isinstance(
                value, EmbeddedDocumentList
            ):
                value = EmbeddedDocumentList(value, instance, self.name)
            elif not isinstance(value, BaseList):
                value = BaseList(value, instance, self.name)
            instance._data[self.name] = value
        elif isinstance(value, dict) and not isinstance(value, BaseDict):
            value = BaseDict(value, instance, self.name)
            instance._data[self.name] = value
        if (
            auto_dereference
            and instance._initialised
            and isinstance(value, (BaseList, BaseDict))
            and not value._dereferenced
        ):
            value = self._lazy_load_refs(
                ref_values=value, instance=instance, name=self.name, max_depth=1
            )
            value._dereferenced = True
            instance._data[self.name] = value
        return value
    def to_python(self, value):
        """Convert a MongoDB-compatible type to a Python type."""
        if isinstance(value, str):
            return value
        if hasattr(value, "to_python"):
            return value.to_python()
        BaseDocument = _import_class("BaseDocument")
        if isinstance(value, BaseDocument):
            # Something is wrong, return the value as it is
            return value
        is_list = False
        if not hasattr(value, "items"):
            try:
                is_list = True
                value = {idx: v for idx, v in enumerate(value)}
            except TypeError:  # Not iterable return the value
                return value
        if self.field:
            self.field._auto_dereference = self._auto_dereference
            value_dict = {
                key: self.field.to_python(item) for key, item in value.items()
            }
        else:
            Document = _import_class("Document")
            value_dict = {}
            for k, v in value.items():
                if isinstance(v, Document):
                    # We need the id from the saved object to create the DBRef
                    if v.pk is None:
                        self.error(
                            "You can only reference documents once they"
                            " have been saved to the database"
                        )
                    collection = v._get_collection_name()
                    value_dict[k] = DBRef(collection, v.pk)
                elif hasattr(v, "to_python"):
                    value_dict[k] = v.to_python()
                else:
                    value_dict[k] = self.to_python(v)
        if is_list:  # Convert back to a list
            return [
                v for _, v in sorted(value_dict.items(), key=operator.itemgetter(0))
            ]
        return value_dict
    def to_mongo(self, value, use_db_field=True, fields=None):
        """Convert a Python type to a MongoDB-compatible type."""
        Document = _import_class("Document")
        EmbeddedDocument = _import_class("EmbeddedDocument")
        GenericReferenceField = _import_class("GenericReferenceField")
        if isinstance(value, str):
            return value
        if hasattr(value, "to_mongo"):
            if isinstance(value, Document):
                return GenericReferenceField().to_mongo(value)
            cls = value.__class__
            val = value.to_mongo(use_db_field, fields)
            # If it's a document that is not inherited add _cls
            if isinstance(value, EmbeddedDocument):
                val["_cls"] = cls.__name__
            return val
        is_list = False
        if not hasattr(value, "items"):
            try:
                is_list = True
                value = {k: v for k, v in enumerate(value)}
            except TypeError:  # Not iterable return the value
                return value
        if self.field:
            value_dict = {
                key: self.field._to_mongo_safe_call(item, use_db_field, fields)
                for key, item in value.items()
            }
        else:
            value_dict = {}
            for k, v in value.items():
                if isinstance(v, Document):
                    # We need the id from the saved object to create the DBRef
                    if v.pk is None:
                        self.error(
                            "You can only reference documents once they"
                            " have been saved to the database"
                        )
                    # If its a document that is not inheritable it won't have
                    # any _cls data so make it a generic reference allows
                    # us to dereference
                    meta = getattr(v, "_meta", {})
                    allow_inheritance = meta.get("allow_inheritance")
                    if not allow_inheritance and not self.field:
                        value_dict[k] = GenericReferenceField().to_mongo(v)
                    else:
                        collection = v._get_collection_name()
                        value_dict[k] = DBRef(collection, v.pk)
                elif hasattr(v, "to_mongo"):
                    cls = v.__class__
                    val = v.to_mongo(use_db_field, fields)
                    # If it's a document that is not inherited add _cls
                    if isinstance(v, (Document, EmbeddedDocument)):
                        val["_cls"] = cls.__name__
                    value_dict[k] = val
                else:
                    value_dict[k] = self.to_mongo(v, use_db_field, fields)
        if is_list:  # Convert back to a list
            return [
                v for _, v in sorted(value_dict.items(), key=operator.itemgetter(0))
            ]
        return value_dict
    def validate(self, value):
        """If field is provided ensure the value is valid."""
        errors = {}
        if self.field:
            if hasattr(value, "items"):
                sequence = value.items()
            else:
                sequence = enumerate(value)
            for k, v in sequence:
                try:
                    self.field._validate(v)
                except ValidationError as error:
                    errors[k] = error.errors or error
                except (ValueError, AssertionError) as error:
                    errors[k] = error
            if errors:
                field_class = self.field.__class__.__name__
                self.error(f"Invalid {field_class} item ({value})", errors=errors)
        # Don't allow empty values if required
        if self.required and not value:
            self.error("Field is required and cannot be empty")
    def prepare_query_value(self, op, value):
        return self.to_mongo(value)
    def lookup_member(self, member_name):
        if self.field:
            return self.field.lookup_member(member_name)
        return None
    def _set_owner_document(self, owner_document):
        if self.field:
            self.field.owner_document = owner_document
        self._owner_document = owner_document
 class ObjectIdField(BaseField):
    """A field wrapper around MongoDB's ObjectIds."""
    def to_python(self, value):
        try:
            if not isinstance(value, ObjectId):
                value = ObjectId(value)
        except Exception:
            pass
        return value
    def to_mongo(self, value):
        if not isinstance(value, ObjectId):
            try:
                return ObjectId(str(value))
            except Exception as e:
                self.error(str(e))
        return value
    def prepare_query_value(self, op, value):
        return self.to_mongo(value)
    def validate(self, value):
        try:
            ObjectId(str(value))
        except Exception:
            self.error("Invalid ObjectID")
 class GeoJsonBaseField(BaseField):
    """A geo json field storing a geojson style object."""
    _geo_index = pymongo.GEOSPHERE
    _type = "GeoBase"
    def __init__(self, auto_index=True, *args, **kwargs):
        """
        :param bool auto_index: Automatically create a '2dsphere' index.\
            Defaults to `True`.
        """
        self._name = "%sField" % self._type
        if not auto_index:
            self._geo_index = False
        super().__init__(*args, **kwargs)
    def validate(self, value):
        """Validate the GeoJson object based on its type."""
        if isinstance(value, dict):
            if set(value.keys()) == {"type", "coordinates"}:
                if value["type"] != self._type:
                    self.error(f'{self._name} type must be "{self._type}"')
                return self.validate(value["coordinates"])
            else:
                self.error(
                    "%s can only accept a valid GeoJson dictionary"
                    " or lists of (x, y)" % self._name
                )
                return
        elif not isinstance(value, (list, tuple)):
            self.error("%s can only accept lists of [x, y]" % self._name)
            return
        validate = getattr(self, "_validate_%s" % self._type.lower())
        error = validate(value)
        if error:
            self.error(error)
    def _validate_polygon(self, value, top_level=True):
        if not isinstance(value, (list, tuple)):
            return "Polygons must contain list of linestrings"
        # Quick and dirty validator
        try:
            value[0][0][0]
        except (TypeError, IndexError):
            return "Invalid Polygon must contain at least one valid linestring"
        errors = []
        for val in value:
            error = self._validate_linestring(val, False)
            if not error and val[0] != val[-1]:
                error = "LineStrings must start and end at the same point"
            if error and error not in errors:
                errors.append(error)
        if errors:
            if top_level:
                return "Invalid Polygon:\n%s" % ", ".join(errors)
            else:
                return "%s" % ", ".join(errors)
    def _validate_linestring(self, value, top_level=True):
        """Validate a linestring."""
        if not isinstance(value, (list, tuple)):
            return "LineStrings must contain list of coordinate pairs"
        # Quick and dirty validator
        try:
            value[0][0]
        except (TypeError, IndexError):
            return "Invalid LineString must contain at least one valid point"
        errors = []
        for val in value:
            error = self._validate_point(val)
            if error and error not in errors:
                errors.append(error)
        if errors:
            if top_level:
                return "Invalid LineString:\n%s" % ", ".join(errors)
            else:
                return "%s" % ", ".join(errors)
    def _validate_point(self, value):
        """Validate each set of coords"""
        if not isinstance(value, (list, tuple)):
            return "Points must be a list of coordinate pairs"
        elif not len(value) == 2:
            return "Value (%s) must be a two-dimensional point" % repr(value)
        elif not isinstance(value[0], (float, int)) or not isinstance(
            value[1], (float, int)
        ):
            return "Both values (%s) in point must be float or int" % repr(value)
    def _validate_multipoint(self, value):
        if not isinstance(value, (list, tuple)):
            return "MultiPoint must be a list of Point"
        # Quick and dirty validator
        try:
            value[0][0]
        except (TypeError, IndexError):
            return "Invalid MultiPoint must contain at least one valid point"
        errors = []
        for point in value:
            error = self._validate_point(point)
            if error and error not in errors:
                errors.append(error)
        if errors:
            return "%s" % ", ".join(errors)
    def _validate_multilinestring(self, value, top_level=True):
        if not isinstance(value, (list, tuple)):
            return "MultiLineString must be a list of LineString"
        # Quick and dirty validator
        try:
            value[0][0][0]
        except (TypeError, IndexError):
            return "Invalid MultiLineString must contain at least one valid linestring"
        errors = []
        for linestring in value:
            error = self._validate_linestring(linestring, False)
            if error and error not in errors:
                errors.append(error)
        if errors:
            if top_level:
                return "Invalid MultiLineString:\n%s" % ", ".join(errors)
            else:
                return "%s" % ", ".join(errors)
    def _validate_multipolygon(self, value):
        if not isinstance(value, (list, tuple)):
            return "MultiPolygon must be a list of Polygon"
        # Quick and dirty validator
        try:
            value[0][0][0][0]
        except (TypeError, IndexError):
            return "Invalid MultiPolygon must contain at least one valid Polygon"
        errors = []
        for polygon in value:
            error = self._validate_polygon(polygon, False)
            if error and error not in errors:
                errors.append(error)
        if errors:
            return "Invalid MultiPolygon:\n%s" % ", ".join(errors)
    def to_mongo(self, value):
        if isinstance(value, dict):
            return value
        return SON([("type", self._type), ("coordinates", value)])
--- a/mongoengine/base/metaclasses.py
+++ b/mongoengine/base/metaclasses.py
@ -1,469 +0,0 @@
 import itertools
 import warnings
 from mongoengine.base.common import _document_registry
 from mongoengine.base.fields import (
    BaseField,
    ComplexBaseField,
    ObjectIdField,
 )
 from mongoengine.common import _import_class
 from mongoengine.errors import InvalidDocumentError
 from mongoengine.queryset import (
    DO_NOTHING,
    DoesNotExist,
    MultipleObjectsReturned,
    QuerySetManager,
 )
 __all__ = ("DocumentMetaclass", "TopLevelDocumentMetaclass")
 class DocumentMetaclass(type):
    """Metaclass for all documents."""
    # TODO lower complexity of this method
    def __new__(mcs, name, bases, attrs):
        flattened_bases = mcs._get_bases(bases)
        super_new = super().__new__
        # If a base class just call super
        metaclass = attrs.get("my_metaclass")
        if metaclass and issubclass(metaclass, DocumentMetaclass):
            return super_new(mcs, name, bases, attrs)
        attrs["_is_document"] = attrs.get("_is_document", False)
        attrs["_cached_reference_fields"] = []
        # EmbeddedDocuments could have meta data for inheritance
        if "meta" in attrs:
            attrs["_meta"] = attrs.pop("meta")
        # EmbeddedDocuments should inherit meta data
        if "_meta" not in attrs:
            meta = MetaDict()
            for base in flattened_bases[::-1]:
                # Add any mixin metadata from plain objects
                if hasattr(base, "meta"):
                    meta.merge(base.meta)
                elif hasattr(base, "_meta"):
                    meta.merge(base._meta)
            attrs["_meta"] = meta
            attrs["_meta"][
                "abstract"
            ] = False  # 789: EmbeddedDocument shouldn't inherit abstract
        # If allow_inheritance is True, add a "_cls" string field to the attrs
        if attrs["_meta"].get("allow_inheritance"):
            StringField = _import_class("StringField")
            attrs["_cls"] = StringField()
        # Handle document Fields
        # Merge all fields from subclasses
        doc_fields = {}
        for base in flattened_bases[::-1]:
            if hasattr(base, "_fields"):
                doc_fields.update(base._fields)
            # Standard object mixin - merge in any Fields
            if not hasattr(base, "_meta"):
                base_fields = {}
                for attr_name, attr_value in base.__dict__.items():
                    if not isinstance(attr_value, BaseField):
                        continue
                    attr_value.name = attr_name
                    if not attr_value.db_field:
                        attr_value.db_field = attr_name
                    base_fields[attr_name] = attr_value
                doc_fields.update(base_fields)
        # Discover any document fields
        field_names = {}
        for attr_name, attr_value in attrs.items():
            if not isinstance(attr_value, BaseField):
                continue
            attr_value.name = attr_name
            if not attr_value.db_field:
                attr_value.db_field = attr_name
            doc_fields[attr_name] = attr_value
            # Count names to ensure no db_field redefinitions
            field_names[attr_value.db_field] = (
                field_names.get(attr_value.db_field, 0) + 1
            )
        # Ensure no duplicate db_fields
        duplicate_db_fields = [k for k, v in field_names.items() if v > 1]
        if duplicate_db_fields:
            msg = "Multiple db_fields defined for: %s " % ", ".join(duplicate_db_fields)
            raise InvalidDocumentError(msg)
        # Set _fields and db_field maps
        attrs["_fields"] = doc_fields
        attrs["_db_field_map"] = {
            k: getattr(v, "db_field", k) for k, v in doc_fields.items()
        }
        attrs["_reverse_db_field_map"] = {
            v: k for k, v in attrs["_db_field_map"].items()
        }
        attrs["_fields_ordered"] = tuple(
            i[1]
            for i in sorted((v.creation_counter, v.name) for v in doc_fields.values())
        )
        #
        # Set document hierarchy
        #
        superclasses = ()
        class_name = [name]
        for base in flattened_bases:
            if not getattr(base, "_is_base_cls", True) and not getattr(
                base, "_meta", {}
            ).get("abstract", True):
                # Collate hierarchy for _cls and _subclasses
                class_name.append(base.__name__)
            if hasattr(base, "_meta"):
                # Warn if allow_inheritance isn't set and prevent
                # inheritance of classes where inheritance is set to False
                allow_inheritance = base._meta.get("allow_inheritance")
                if not allow_inheritance and not base._meta.get("abstract"):
                    raise ValueError(
                        "Document %s may not be subclassed. "
                        'To enable inheritance, use the "allow_inheritance" meta attribute.'
                        % base.__name__
                    )
        # Get superclasses from last base superclass
        document_bases = [b for b in flattened_bases if hasattr(b, "_class_name")]
        if document_bases:
            superclasses = document_bases[0]._superclasses
            superclasses += (document_bases[0]._class_name,)
        _cls = ".".join(reversed(class_name))
        attrs["_class_name"] = _cls
        attrs["_superclasses"] = superclasses
        attrs["_subclasses"] = (_cls,)
        attrs["_types"] = attrs["_subclasses"]  # TODO depreciate _types
        # Create the new_class
        new_class = super_new(mcs, name, bases, attrs)
        # Set _subclasses
        for base in document_bases:
            if _cls not in base._subclasses:
                base._subclasses += (_cls,)
            base._types = base._subclasses  # TODO depreciate _types
        (
            Document,
            EmbeddedDocument,
            DictField,
            CachedReferenceField,
        ) = mcs._import_classes()
        if issubclass(new_class, Document):
            new_class._collection = None
        # Add class to the _document_registry
        _document_registry[new_class._class_name] = new_class
        # Handle delete rules
        for field in new_class._fields.values():
            f = field
            if f.owner_document is None:
                f.owner_document = new_class
            delete_rule = getattr(f, "reverse_delete_rule", DO_NOTHING)
            if isinstance(f, CachedReferenceField):
                if issubclass(new_class, EmbeddedDocument):
                    raise InvalidDocumentError(
                        "CachedReferenceFields is not allowed in EmbeddedDocuments"
                    )
                if f.auto_sync:
                    f.start_listener()
                f.document_type._cached_reference_fields.append(f)
            if isinstance(f, ComplexBaseField) and hasattr(f, "field"):
                delete_rule = getattr(f.field, "reverse_delete_rule", DO_NOTHING)
                if isinstance(f, DictField) and delete_rule != DO_NOTHING:
                    msg = (
                        "Reverse delete rules are not supported "
                        "for %s (field: %s)" % (field.__class__.__name__, field.name)
                    )
                    raise InvalidDocumentError(msg)
                f = field.field
            if delete_rule != DO_NOTHING:
                if issubclass(new_class, EmbeddedDocument):
                    msg = (
                        "Reverse delete rules are not supported for "
                        "EmbeddedDocuments (field: %s)" % field.name
                    )
                    raise InvalidDocumentError(msg)
                f.document_type.register_delete_rule(new_class, field.name, delete_rule)
            if (
                field.name
                and hasattr(Document, field.name)
                and EmbeddedDocument not in new_class.mro()
            ):
                msg = "%s is a document method and not a valid field name" % field.name
                raise InvalidDocumentError(msg)
        return new_class
    @classmethod
    def _get_bases(mcs, bases):
        if isinstance(bases, BasesTuple):
            return bases
        seen = []
        bases = mcs.__get_bases(bases)
        unique_bases = (b for b in bases if not (b in seen or seen.append(b)))
        return BasesTuple(unique_bases)
    @classmethod
    def __get_bases(mcs, bases):
        for base in bases:
            if base is object:
                continue
            yield base
            yield from mcs.__get_bases(base.__bases__)
    @classmethod
    def _import_classes(mcs):
        Document = _import_class("Document")
        EmbeddedDocument = _import_class("EmbeddedDocument")
        DictField = _import_class("DictField")
        CachedReferenceField = _import_class("CachedReferenceField")
        return Document, EmbeddedDocument, DictField, CachedReferenceField
 class TopLevelDocumentMetaclass(DocumentMetaclass):
    """Metaclass for top-level documents (i.e. documents that have their own
    collection in the database.
    """
    def __new__(mcs, name, bases, attrs):
        flattened_bases = mcs._get_bases(bases)
        super_new = super().__new__
        # Set default _meta data if base class, otherwise get user defined meta
        if attrs.get("my_metaclass") == TopLevelDocumentMetaclass:
            # defaults
            attrs["_meta"] = {
                "abstract": True,
                "max_documents": None,
                "max_size": None,
                "ordering": [],  # default ordering applied at runtime
                "indexes": [],  # indexes to be ensured at runtime
                "id_field": None,
                "index_background": False,
                "index_opts": None,
                "delete_rules": None,
                # allow_inheritance can be True, False, and None. True means
                # "allow inheritance", False means "don't allow inheritance",
                # None means "do whatever your parent does, or don't allow
                # inheritance if you're a top-level class".
                "allow_inheritance": None,
            }
            attrs["_is_base_cls"] = True
            attrs["_meta"].update(attrs.get("meta", {}))
        else:
            attrs["_meta"] = attrs.get("meta", {})
            # Explicitly set abstract to false unless set
            attrs["_meta"]["abstract"] = attrs["_meta"].get("abstract", False)
            attrs["_is_base_cls"] = False
        # Set flag marking as document class - as opposed to an object mixin
        attrs["_is_document"] = True
        # Ensure queryset_class is inherited
        if "objects" in attrs:
            manager = attrs["objects"]
            if hasattr(manager, "queryset_class"):
                attrs["_meta"]["queryset_class"] = manager.queryset_class
        # Clean up top level meta
        if "meta" in attrs:
            del attrs["meta"]
        # Find the parent document class
        parent_doc_cls = [
            b for b in flattened_bases if b.__class__ == TopLevelDocumentMetaclass
        ]
        parent_doc_cls = None if not parent_doc_cls else parent_doc_cls[0]
        # Prevent classes setting collection different to their parents
        # If parent wasn't an abstract class
        if (
            parent_doc_cls
            and "collection" in attrs.get("_meta", {})
            and not parent_doc_cls._meta.get("abstract", True)
        ):
            msg = "Trying to set a collection on a subclass (%s)" % name
            warnings.warn(msg, SyntaxWarning)
            del attrs["_meta"]["collection"]
        # Ensure abstract documents have abstract bases
        if attrs.get("_is_base_cls") or attrs["_meta"].get("abstract"):
            if parent_doc_cls and not parent_doc_cls._meta.get("abstract", False):
                msg = "Abstract document cannot have non-abstract base"
                raise ValueError(msg)
            return super_new(mcs, name, bases, attrs)
        # Merge base class metas.
        # Uses a special MetaDict that handles various merging rules
        meta = MetaDict()
        for base in flattened_bases[::-1]:
            # Add any mixin metadata from plain objects
            if hasattr(base, "meta"):
                meta.merge(base.meta)
            elif hasattr(base, "_meta"):
                meta.merge(base._meta)
            # Set collection in the meta if its callable
            if getattr(base, "_is_document", False) and not base._meta.get("abstract"):
                collection = meta.get("collection", None)
                if callable(collection):
                    meta["collection"] = collection(base)
        meta.merge(attrs.get("_meta", {}))  # Top level meta
        # Only simple classes (i.e. direct subclasses of Document) may set
        # allow_inheritance to False. If the base Document allows inheritance,
        # none of its subclasses can override allow_inheritance to False.
        simple_class = all(
            b._meta.get("abstract") for b in flattened_bases if hasattr(b, "_meta")
        )
        if (
            not simple_class
            and meta["allow_inheritance"] is False
            and not meta["abstract"]
        ):
            raise ValueError(
                "Only direct subclasses of Document may set "
                '"allow_inheritance" to False'
            )
        # Set default collection name
        if "collection" not in meta:
            meta["collection"] = (
                "".join("_%s" % c if c.isupper() else c for c in name)
                .strip("_")
                .lower()
            )
        attrs["_meta"] = meta
        # Call super and get the new class
        new_class = super_new(mcs, name, bases, attrs)
        meta = new_class._meta
        # Set index specifications
        meta["index_specs"] = new_class._build_index_specs(meta["indexes"])
        # If collection is a callable - call it and set the value
        collection = meta.get("collection")
        if callable(collection):
            new_class._meta["collection"] = collection(new_class)
        # Provide a default queryset unless exists or one has been set
        if "objects" not in dir(new_class):
            new_class.objects = QuerySetManager()
        # Validate the fields and set primary key if needed
        for field_name, field in new_class._fields.items():
            if field.primary_key:
                # Ensure only one primary key is set
                current_pk = new_class._meta.get("id_field")
                if current_pk and current_pk != field_name:
                    raise ValueError("Cannot override primary key field")
                # Set primary key
                if not current_pk:
                    new_class._meta["id_field"] = field_name
                    new_class.id = field
        # If the document doesn't explicitly define a primary key field, create
        # one. Make it an ObjectIdField and give it a non-clashing name ("id"
        # by default, but can be different if that one's taken).
        if not new_class._meta.get("id_field"):
            id_name, id_db_name = mcs.get_auto_id_names(new_class)
            new_class._meta["id_field"] = id_name
            new_class._fields[id_name] = ObjectIdField(db_field=id_db_name)
            new_class._fields[id_name].name = id_name
            new_class.id = new_class._fields[id_name]
            new_class._db_field_map[id_name] = id_db_name
            new_class._reverse_db_field_map[id_db_name] = id_name
            # Prepend the ID field to _fields_ordered (so that it's *always*
            # the first field).
            new_class._fields_ordered = (id_name,) + new_class._fields_ordered
        # Merge in exceptions with parent hierarchy.
        exceptions_to_merge = (DoesNotExist, MultipleObjectsReturned)
        module = attrs.get("__module__")
        for exc in exceptions_to_merge:
            name = exc.__name__
            parents = tuple(
                getattr(base, name) for base in flattened_bases if hasattr(base, name)
            ) or (exc,)
            # Create a new exception and set it as an attribute on the new
            # class.
            exception = type(name, parents, {"__module__": module})
            setattr(new_class, name, exception)
        return new_class
    @classmethod
    def get_auto_id_names(mcs, new_class):
        """Find a name for the automatic ID field for the given new class.
        Return a two-element tuple where the first item is the field name (i.e.
        the attribute name on the object) and the second element is the DB
        field name (i.e. the name of the key stored in MongoDB).
        Defaults to ('id', '_id'), or generates a non-clashing name in the form
        of ('auto_id_X', '_auto_id_X') if the default name is already taken.
        """
        id_name, id_db_name = ("id", "_id")
        existing_fields = {field_name for field_name in new_class._fields}
        existing_db_fields = {v.db_field for v in new_class._fields.values()}
        if id_name not in existing_fields and id_db_name not in existing_db_fields:
            return id_name, id_db_name
        id_basename, id_db_basename, i = ("auto_id", "_auto_id", 0)
        for i in itertools.count():
            id_name = f"{id_basename}_{i}"
            id_db_name = f"{id_db_basename}_{i}"
            if id_name not in existing_fields and id_db_name not in existing_db_fields:
                return id_name, id_db_name
 class MetaDict(dict):
    """Custom dictionary for meta classes.
    Handles the merging of set indexes
    """
    _merge_options = ("indexes",)
    def merge(self, new_options):
        for k, v in new_options.items():
            if k in self._merge_options:
                self[k] = self.get(k, []) + v
            else:
                self[k] = v
 class BasesTuple(tuple):
    """Special class to handle introspection of bases tuple in __new__"""
    pass
--- a/mongoengine/base/utils.py
+++ b/mongoengine/base/utils.py
@ -1,22 +0,0 @@
 import re
 class LazyRegexCompiler:
    """Descriptor to allow lazy compilation of regex"""
    def __init__(self, pattern, flags=0):
        self._pattern = pattern
        self._flags = flags
        self._compiled_regex = None
    @property
    def compiled_regex(self):
        if self._compiled_regex is None:
            self._compiled_regex = re.compile(self._pattern, self._flags)
        return self._compiled_regex
    def __get__(self, instance, owner):
        return self.compiled_regex
    def __set__(self, instance, value):
        raise AttributeError("Can not set attribute LazyRegexCompiler")
--- a/mongoengine/common.py
+++ b/mongoengine/common.py
@ -1,64 +0,0 @@
 _class_registry_cache = {}
 _field_list_cache = []
 def _import_class(cls_name):
    """Cache mechanism for imports.
    Due to complications of circular imports mongoengine needs to do lots of
    inline imports in functions.  This is inefficient as classes are
    imported repeated throughout the mongoengine code.  This is
    compounded by some recursive functions requiring inline imports.
    :mod:`mongoengine.common` provides a single point to import all these
    classes.  Circular imports aren't an issue as it dynamically imports the
    class when first needed.  Subsequent calls to the
    :func:`~mongoengine.common._import_class` can then directly retrieve the
    class from the :data:`mongoengine.common._class_registry_cache`.
    """
    if cls_name in _class_registry_cache:
        return _class_registry_cache.get(cls_name)
    doc_classes = (
        "Document",
        "DynamicEmbeddedDocument",
        "EmbeddedDocument",
        "MapReduceDocument",
    )
    # Field Classes
    if not _field_list_cache:
        from mongoengine.fields import __all__ as fields
        _field_list_cache.extend(fields)
        from mongoengine.base.fields import __all__ as fields
        _field_list_cache.extend(fields)
    field_classes = _field_list_cache
    deref_classes = ("DeReference",)
    if cls_name == "BaseDocument":
        from mongoengine.base import document as module
        import_classes = ["BaseDocument"]
    elif cls_name in doc_classes:
        from mongoengine import document as module
        import_classes = doc_classes
    elif cls_name in field_classes:
        from mongoengine import fields as module
        import_classes = field_classes
    elif cls_name in deref_classes:
        from mongoengine import dereference as module
        import_classes = deref_classes
    else:
        raise ValueError("No import set for: %s" % cls_name)
    for cls in import_classes:
        _class_registry_cache[cls] = getattr(module, cls)
    return _class_registry_cache.get(cls_name)
--- a/mongoengine/connection.py
+++ b/mongoengine/connection.py
@ -1,403 +1,166 @@
-from pymongo import MongoClient, ReadPreference, uri_parser
+import pymongo
-from pymongo.database import _check_name
+from pymongo import Connection, ReplicaSetConnection, uri_parser
 __all__ = [
    "DEFAULT_CONNECTION_NAME",
    "DEFAULT_DATABASE_NAME",
    "ConnectionFailure",
    "connect",
    "disconnect",
    "disconnect_all",
    "get_connection",
    "get_db",
    "register_connection",
 ]
-DEFAULT_CONNECTION_NAME = "default"
+__all__ = ['ConnectionError', 'connect', 'register_connection',
-DEFAULT_DATABASE_NAME = "test"
+           'DEFAULT_CONNECTION_NAME']
-DEFAULT_HOST = "localhost"
+
-DEFAULT_PORT = 27017
+
 DEFAULT_CONNECTION_NAME = 'default'
 class ConnectionError(Exception):
    pass
 _connection_settings = {}
 _connections = {}
 _dbs = {}
 READ_PREFERENCE = ReadPreference.PRIMARY
 def register_connection(alias, name, host='localhost', port=27017,
                        is_slave=False, read_preference=False, slaves=None,
                        username=None, password=None, **kwargs):
    """Add a connection.
-class ConnectionFailure(Exception):
+    :param alias: the name that will be used to refer to this connection
-    """Error raised when the database connection can't be established or
+        throughout MongoEngine
    when a connection with a requested alias can't be retrieved.
    """
    pass
 def _check_db_name(name):
    """Check if a database name is valid.
    This functionality is copied from pymongo Database class constructor.
    """
    if not isinstance(name, str):
        raise TypeError("name must be an instance of %s" % str)
    elif name != "$external":
        _check_name(name)
 def _get_connection_settings(
    db=None,
    name=None,
    host=None,
    port=None,
    read_preference=READ_PREFERENCE,
    username=None,
    password=None,
    authentication_source=None,
    authentication_mechanism=None,
    **kwargs,
 ):
    """Get the connection settings as a dict
    :param db: the name of the database to use, for compatibility with connect
    :param name: the name of the specific database to use
-    :param host: the host name of the: program: `mongod` instance to connect to
+    :param host: the host name of the :program:`mongod` instance to connect to
-    :param port: the port that the: program: `mongod` instance is running on
+    :param port: the port that the :program:`mongod` instance is running on
-    :param read_preference: The read preference for the collection
+    :param is_slave: whether the connection can act as a slave ** Depreciated pymongo 2.0.1+
    :param read_preference: The read preference for the collection ** Added pymongo 2.1
    :param slaves: a list of aliases of slave connections; each of these must
        be a registered connection that has :attr:`is_slave` set to ``True``
    :param username: username to authenticate with
    :param password: password to authenticate with
-    :param authentication_source: database to authenticate against
+    :param kwargs: allow ad-hoc parameters to be passed into the pymongo driver
-    :param authentication_mechanism: database authentication mechanisms.
+
        By default, use SCRAM-SHA-1 with MongoDB 3.0 and later,
        MONGODB-CR (MongoDB Challenge Response protocol) for older servers.
    :param is_mock: explicitly use mongomock for this connection
        (can also be done by using `mongomock: // ` as db host prefix)
    :param kwargs: ad-hoc parameters to be passed into the pymongo driver,
        for example maxpoolsize, tz_aware, etc. See the documentation
        for pymongo's `MongoClient` for a full list.
    """
    global _connection_settings
    conn_settings = {
-        "name": name or db or DEFAULT_DATABASE_NAME,
+        'name': name,
-        "host": host or DEFAULT_HOST,
+        'host': host,
-        "port": port or DEFAULT_PORT,
+        'port': port,
-        "read_preference": read_preference,
+        'is_slave': is_slave,
-        "username": username,
+        'slaves': slaves or [],
-        "password": password,
+        'username': username,
-        "authentication_source": authentication_source,
+        'password': password,
-        "authentication_mechanism": authentication_mechanism,
+        'read_preference': read_preference
    }
-    _check_db_name(conn_settings["name"])
+    # Handle uri style connections
-    conn_host = conn_settings["host"]
+    if "://" in host:
-
+        uri_dict = uri_parser.parse_uri(host)
-    # Host can be a list or a string, so if string, force to a list.
+        if uri_dict.get('database') is None:
-    if isinstance(conn_host, str):
+            raise ConnectionError("If using URI style connection include "\
-        conn_host = [conn_host]
+                                  "database name in string")
-
+        conn_settings.update({
-    resolved_hosts = []
+            'host': host,
-    for entity in conn_host:
+            'name': uri_dict.get('database'),
-
+            'username': uri_dict.get('username'),
-        # Handle Mongomock
+            'password': uri_dict.get('password'),
-        if entity.startswith("mongomock://"):
+            'read_preference': read_preference,
-            conn_settings["is_mock"] = True
+        })
-            # `mongomock://` is not a valid url prefix and must be replaced by `mongodb://`
+        if "replicaSet" in host:
-            new_entity = entity.replace("mongomock://", "mongodb://", 1)
+            conn_settings['replicaSet'] = True
            resolved_hosts.append(new_entity)
            uri_dict = uri_parser.parse_uri(new_entity)
            database = uri_dict.get("database")
            if database:
                conn_settings["name"] = database
        # Handle URI style connections, only updating connection params which
        # were explicitly specified in the URI.
        elif "://" in entity:
            uri_dict = uri_parser.parse_uri(entity)
            resolved_hosts.append(entity)
            database = uri_dict.get("database")
            if database:
                conn_settings["name"] = database
            for param in ("read_preference", "username", "password"):
                if uri_dict.get(param):
                    conn_settings[param] = uri_dict[param]
            uri_options = uri_dict["options"]
            if "replicaset" in uri_options:
                conn_settings["replicaSet"] = uri_options["replicaset"]
            if "authsource" in uri_options:
                conn_settings["authentication_source"] = uri_options["authsource"]
            if "authmechanism" in uri_options:
                conn_settings["authentication_mechanism"] = uri_options["authmechanism"]
            if "readpreference" in uri_options:
                read_preferences = (
                    ReadPreference.NEAREST,
                    ReadPreference.PRIMARY,
                    ReadPreference.PRIMARY_PREFERRED,
                    ReadPreference.SECONDARY,
                    ReadPreference.SECONDARY_PREFERRED,
                )
                # Starting with PyMongo v3.5, the "readpreference" option is
                # returned as a string (e.g. "secondaryPreferred") and not an
                # int (e.g. 3).
                # TODO simplify the code below once we drop support for
                # PyMongo v3.4.
                read_pf_mode = uri_options["readpreference"]
                if isinstance(read_pf_mode, str):
                    read_pf_mode = read_pf_mode.lower()
                for preference in read_preferences:
                    if (
                        preference.name.lower() == read_pf_mode
                        or preference.mode == read_pf_mode
                    ):
                        conn_settings["read_preference"] = preference
                        break
        else:
            resolved_hosts.append(entity)
    conn_settings["host"] = resolved_hosts
    # Deprecated parameters that should not be passed on
    kwargs.pop("slaves", None)
    kwargs.pop("is_slave", None)
    conn_settings.update(kwargs)
    return conn_settings
 def register_connection(
    alias,
    db=None,
    name=None,
    host=None,
    port=None,
    read_preference=READ_PREFERENCE,
    username=None,
    password=None,
    authentication_source=None,
    authentication_mechanism=None,
    **kwargs,
 ):
    """Register the connection settings.
    :param alias: the name that will be used to refer to this connection throughout MongoEngine
    :param db: the name of the database to use, for compatibility with connect
    :param name: the name of the specific database to use
    :param host: the host name of the: program: `mongod` instance to connect to
    :param port: the port that the: program: `mongod` instance is running on
    :param read_preference: The read preference for the collection
    :param username: username to authenticate with
    :param password: password to authenticate with
    :param authentication_source: database to authenticate against
    :param authentication_mechanism: database authentication mechanisms.
        By default, use SCRAM-SHA-1 with MongoDB 3.0 and later,
        MONGODB-CR (MongoDB Challenge Response protocol) for older servers.
    :param is_mock: explicitly use mongomock for this connection
        (can also be done by using `mongomock: // ` as db host prefix)
    :param kwargs: ad-hoc parameters to be passed into the pymongo driver,
        for example maxpoolsize, tz_aware, etc. See the documentation
        for pymongo's `MongoClient` for a full list.
    """
    conn_settings = _get_connection_settings(
        db=db,
        name=name,
        host=host,
        port=port,
        read_preference=read_preference,
        username=username,
        password=password,
        authentication_source=authentication_source,
        authentication_mechanism=authentication_mechanism,
        **kwargs,
    )
    _connection_settings[alias] = conn_settings
 def disconnect(alias=DEFAULT_CONNECTION_NAME):
-    """Close the connection with a given alias."""
+    global _connections
-    from mongoengine import Document
+    global _dbs
    from mongoengine.base.common import _get_documents_by_db
    if alias in _connections:
-        get_connection(alias=alias).close()
+        get_connection(alias=alias).disconnect()
        del _connections[alias]
    if alias in _dbs:
        # Detach all cached collections in Documents
        for doc_cls in _get_documents_by_db(alias, DEFAULT_CONNECTION_NAME):
            if issubclass(doc_cls, Document):  # Skip EmbeddedDocument
                doc_cls._disconnect()
        del _dbs[alias]
    if alias in _connection_settings:
        del _connection_settings[alias]
 def disconnect_all():
    """Close all registered database."""
    for alias in list(_connections.keys()):
        disconnect(alias)
 def get_connection(alias=DEFAULT_CONNECTION_NAME, reconnect=False):
-    """Return a connection with a given alias."""
+    global _connections
    # Connect to the database if not already connected
    if reconnect:
        disconnect(alias)
-    # If the requested alias already exists in the _connections list, return
+    if alias not in _connections:
-    # it immediately.
+        if alias not in _connection_settings:
    if alias in _connections:
        return _connections[alias]
    # Validate that the requested alias exists in the _connection_settings.
    # Raise ConnectionFailure if it doesn't.
    if alias not in _connection_settings:
        if alias == DEFAULT_CONNECTION_NAME:
            msg = "You have not defined a default connection"
        else:
            msg = 'Connection with alias "%s" has not been defined' % alias
-        raise ConnectionFailure(msg)
+            if alias == DEFAULT_CONNECTION_NAME:
                msg = 'You have not defined a default connection'
            raise ConnectionError(msg)
        conn_settings = _connection_settings[alias].copy()
-    def _clean_settings(settings_dict):
+        if hasattr(pymongo, 'version_tuple'):  # Support for 2.1+
-        irrelevant_fields_set = {
+            conn_settings.pop('name', None)
-            "name",
+            conn_settings.pop('slaves', None)
-            "username",
+            conn_settings.pop('is_slave', None)
-            "password",
+            conn_settings.pop('username', None)
-            "authentication_source",
+            conn_settings.pop('password', None)
-            "authentication_mechanism",
+        else:
-        }
+            # Get all the slave connections
-        return {
+            if 'slaves' in conn_settings:
-            k: v for k, v in settings_dict.items() if k not in irrelevant_fields_set
+                slaves = []
-        }
+                for slave_alias in conn_settings['slaves']:
                    slaves.append(get_connection(slave_alias))
                conn_settings['slaves'] = slaves
                conn_settings.pop('read_preference', None)
-    raw_conn_settings = _connection_settings[alias].copy()
+        connection_class = Connection
        if 'replicaSet' in conn_settings:
            conn_settings['hosts_or_uri'] = conn_settings.pop('host', None)
            # Discard port since it can't be used on ReplicaSetConnection
            conn_settings.pop('port', None)
            # Discard replicaSet if not base string
            if not isinstance(conn_settings['replicaSet'], basestring):
                conn_settings.pop('replicaSet', None)
            connection_class = ReplicaSetConnection
    # Retrieve a copy of the connection settings associated with the requested
    # alias and remove the database name and authentication info (we don't
    # care about them at this point).
    conn_settings = _clean_settings(raw_conn_settings)
    # Determine if we should use PyMongo's or mongomock's MongoClient.
    is_mock = conn_settings.pop("is_mock", False)
    if is_mock:
        try:
-            import mongomock
+            _connections[alias] = connection_class(**conn_settings)
-        except ImportError:
+        except Exception, e:
-            raise RuntimeError("You need mongomock installed to mock MongoEngine.")
+            raise ConnectionError("Cannot connect to database %s :\n%s" % (alias, e))
        connection_class = mongomock.MongoClient
    else:
        connection_class = MongoClient
    # Re-use existing connection if one is suitable.
    existing_connection = _find_existing_connection(raw_conn_settings)
    if existing_connection:
        connection = existing_connection
    else:
        connection = _create_connection(
            alias=alias, connection_class=connection_class, **conn_settings
        )
    _connections[alias] = connection
    return _connections[alias]
 def _create_connection(alias, connection_class, **connection_settings):
    """
    Create the new connection for this alias. Raise
    ConnectionFailure if it can't be established.
    """
    try:
        return connection_class(**connection_settings)
    except Exception as e:
        raise ConnectionFailure(f"Cannot connect to database {alias} :\n{e}")
 def _find_existing_connection(connection_settings):
    """
    Check if an existing connection could be reused
    Iterate over all of the connection settings and if an existing connection
    with the same parameters is suitable, return it
    :param connection_settings: the settings of the new connection
    :return: An existing connection or None
    """
    connection_settings_bis = (
        (db_alias, settings.copy())
        for db_alias, settings in _connection_settings.items()
    )
    def _clean_settings(settings_dict):
        # Only remove the name but it's important to
        # keep the username/password/authentication_source/authentication_mechanism
        # to identify if the connection could be shared (cfr https://github.com/MongoEngine/mongoengine/issues/2047)
        return {k: v for k, v in settings_dict.items() if k != "name"}
    cleaned_conn_settings = _clean_settings(connection_settings)
    for db_alias, connection_settings in connection_settings_bis:
        db_conn_settings = _clean_settings(connection_settings)
        if cleaned_conn_settings == db_conn_settings and _connections.get(db_alias):
            return _connections[db_alias]
 def get_db(alias=DEFAULT_CONNECTION_NAME, reconnect=False):
    global _dbs
    if reconnect:
        disconnect(alias)
    if alias not in _dbs:
        conn = get_connection(alias)
        conn_settings = _connection_settings[alias]
-        db = conn[conn_settings["name"]]
+        _dbs[alias] = conn[conn_settings['name']]
        auth_kwargs = {"source": conn_settings["authentication_source"]}
        if conn_settings["authentication_mechanism"] is not None:
            auth_kwargs["mechanism"] = conn_settings["authentication_mechanism"]
        # Authenticate if necessary
-        if conn_settings["username"] and (
+        if conn_settings['username'] and conn_settings['password']:
-            conn_settings["password"]
+            _dbs[alias].authenticate(conn_settings['username'],
-            or conn_settings["authentication_mechanism"] == "MONGODB-X509"
+                                     conn_settings['password'])
        ):
            db.authenticate(
                conn_settings["username"], conn_settings["password"], **auth_kwargs
            )
        _dbs[alias] = db
    return _dbs[alias]
-def connect(db=None, alias=DEFAULT_CONNECTION_NAME, **kwargs):
+def connect(db, alias=DEFAULT_CONNECTION_NAME, **kwargs):
    """Connect to the database specified by the 'db' argument.
    Connection settings may be provided here as well if the database is not
    running on the default port on localhost. If authentication is needed,
    provide username and password arguments as well.
-    Multiple databases are supported by using aliases. Provide a separate
+    Multiple databases are supported by using aliases.  Provide a separate
-    `alias` to connect to a different instance of: program: `mongod`.
+    `alias` to connect to a different instance of :program:`mongod`.
-    In order to replace a connection identified by a given alias, you'll
+    .. versionchanged:: 0.6 - added multiple database support.
    need to call ``disconnect`` first
    See the docstring for `register_connection` for more details about all
    supported kwargs.
    """
-    if alias in _connections:
+    global _connections
-        prev_conn_setting = _connection_settings[alias]
+    if alias not in _connections:
        new_conn_settings = _get_connection_settings(db, **kwargs)
        if new_conn_settings != prev_conn_setting:
            err_msg = (
                "A different connection with alias `{}` was already "
                "registered. Use disconnect() first"
            ).format(alias)
            raise ConnectionFailure(err_msg)
    else:
        register_connection(alias, db, **kwargs)
    return get_connection(alias)
 # Support old naming convention
 _get_connection = get_connection
 _get_db = get_db
--- a/mongoengine/context_managers.py
+++ b/mongoengine/context_managers.py
@ -1,291 +0,0 @@
 from contextlib import contextmanager
 from pymongo.read_concern import ReadConcern
 from pymongo.write_concern import WriteConcern
 from mongoengine.common import _import_class
 from mongoengine.connection import DEFAULT_CONNECTION_NAME, get_db
 from mongoengine.pymongo_support import count_documents
 __all__ = (
    "switch_db",
    "switch_collection",
    "no_dereference",
    "no_sub_classes",
    "query_counter",
    "set_write_concern",
    "set_read_write_concern",
 )
 class switch_db:
    """switch_db alias context manager.
    Example ::
        # Register connections
        register_connection('default', 'mongoenginetest')
        register_connection('testdb-1', 'mongoenginetest2')
        class Group(Document):
            name = StringField()
        Group(name='test').save()  # Saves in the default db
        with switch_db(Group, 'testdb-1') as Group:
            Group(name='hello testdb!').save()  # Saves in testdb-1
    """
    def __init__(self, cls, db_alias):
        """Construct the switch_db context manager
        :param cls: the class to change the registered db
        :param db_alias: the name of the specific database to use
        """
        self.cls = cls
        self.collection = cls._get_collection()
        self.db_alias = db_alias
        self.ori_db_alias = cls._meta.get("db_alias", DEFAULT_CONNECTION_NAME)
    def __enter__(self):
        """Change the db_alias and clear the cached collection."""
        self.cls._meta["db_alias"] = self.db_alias
        self.cls._collection = None
        return self.cls
    def __exit__(self, t, value, traceback):
        """Reset the db_alias and collection."""
        self.cls._meta["db_alias"] = self.ori_db_alias
        self.cls._collection = self.collection
 class switch_collection:
    """switch_collection alias context manager.
    Example ::
        class Group(Document):
            name = StringField()
        Group(name='test').save()  # Saves in the default db
        with switch_collection(Group, 'group1') as Group:
            Group(name='hello testdb!').save()  # Saves in group1 collection
    """
    def __init__(self, cls, collection_name):
        """Construct the switch_collection context manager.
        :param cls: the class to change the registered db
        :param collection_name: the name of the collection to use
        """
        self.cls = cls
        self.ori_collection = cls._get_collection()
        self.ori_get_collection_name = cls._get_collection_name
        self.collection_name = collection_name
    def __enter__(self):
        """Change the _get_collection_name and clear the cached collection."""
        @classmethod
        def _get_collection_name(cls):
            return self.collection_name
        self.cls._get_collection_name = _get_collection_name
        self.cls._collection = None
        return self.cls
    def __exit__(self, t, value, traceback):
        """Reset the collection."""
        self.cls._collection = self.ori_collection
        self.cls._get_collection_name = self.ori_get_collection_name
 class no_dereference:
    """no_dereference context manager.
    Turns off all dereferencing in Documents for the duration of the context
    manager::
        with no_dereference(Group) as Group:
            Group.objects.find()
    """
    def __init__(self, cls):
        """Construct the no_dereference context manager.
        :param cls: the class to turn dereferencing off on
        """
        self.cls = cls
        ReferenceField = _import_class("ReferenceField")
        GenericReferenceField = _import_class("GenericReferenceField")
        ComplexBaseField = _import_class("ComplexBaseField")
        self.deref_fields = [
            k
            for k, v in self.cls._fields.items()
            if isinstance(v, (ReferenceField, GenericReferenceField, ComplexBaseField))
        ]
    def __enter__(self):
        """Change the objects default and _auto_dereference values."""
        for field in self.deref_fields:
            self.cls._fields[field]._auto_dereference = False
        return self.cls
    def __exit__(self, t, value, traceback):
        """Reset the default and _auto_dereference values."""
        for field in self.deref_fields:
            self.cls._fields[field]._auto_dereference = True
        return self.cls
 class no_sub_classes:
    """no_sub_classes context manager.
    Only returns instances of this class and no sub (inherited) classes::
        with no_sub_classes(Group) as Group:
            Group.objects.find()
    """
    def __init__(self, cls):
        """Construct the no_sub_classes context manager.
        :param cls: the class to turn querying sub classes on
        """
        self.cls = cls
        self.cls_initial_subclasses = None
    def __enter__(self):
        """Change the objects default and _auto_dereference values."""
        self.cls_initial_subclasses = self.cls._subclasses
        self.cls._subclasses = (self.cls._class_name,)
        return self.cls
    def __exit__(self, t, value, traceback):
        """Reset the default and _auto_dereference values."""
        self.cls._subclasses = self.cls_initial_subclasses
 class query_counter:
    """Query_counter context manager to get the number of queries.
    This works by updating the `profiling_level` of the database so that all queries get logged,
    resetting the db.system.profile collection at the beginning of the context and counting the new entries.
    This was designed for debugging purpose. In fact it is a global counter so queries issued by other threads/processes
    can interfere with it
    Usage:
    .. code-block:: python
        class User(Document):
            name = StringField()
        with query_counter() as q:
            user = User(name='Bob')
            assert q == 0       # no query fired yet
            user.save()
            assert q == 1       # 1 query was fired, an 'insert'
            user_bis = User.objects().first()
            assert q == 2       # a 2nd query was fired, a 'find_one'
    Be aware that:
    - Iterating over large amount of documents (>101) makes pymongo issue `getmore` queries to fetch the next batch of documents (https://docs.mongodb.com/manual/tutorial/iterate-a-cursor/#cursor-batches)
    - Some queries are ignored by default by the counter (killcursors, db.system.indexes)
    """
    def __init__(self, alias=DEFAULT_CONNECTION_NAME):
        self.db = get_db(alias=alias)
        self.initial_profiling_level = None
        self._ctx_query_counter = 0  # number of queries issued by the context
        self._ignored_query = {
            "ns": {"$ne": "%s.system.indexes" % self.db.name},
            "op": {"$ne": "killcursors"},  # MONGODB < 3.2
            "command.killCursors": {"$exists": False},  # MONGODB >= 3.2
        }
    def _turn_on_profiling(self):
        self.initial_profiling_level = self.db.profiling_level()
        self.db.set_profiling_level(0)
        self.db.system.profile.drop()
        self.db.set_profiling_level(2)
    def _resets_profiling(self):
        self.db.set_profiling_level(self.initial_profiling_level)
    def __enter__(self):
        self._turn_on_profiling()
        return self
    def __exit__(self, t, value, traceback):
        self._resets_profiling()
    def __eq__(self, value):
        counter = self._get_count()
        return value == counter
    def __ne__(self, value):
        return not self.__eq__(value)
    def __lt__(self, value):
        return self._get_count() < value
    def __le__(self, value):
        return self._get_count() <= value
    def __gt__(self, value):
        return self._get_count() > value
    def __ge__(self, value):
        return self._get_count() >= value
    def __int__(self):
        return self._get_count()
    def __repr__(self):
        """repr query_counter as the number of queries."""
        return "%s" % self._get_count()
    def _get_count(self):
        """Get the number of queries by counting the current number of entries in db.system.profile
        and substracting the queries issued by this context. In fact everytime this is called, 1 query is
        issued so we need to balance that
        """
        count = (
            count_documents(self.db.system.profile, self._ignored_query)
            - self._ctx_query_counter
        )
        self._ctx_query_counter += (
            1  # Account for the query we just issued to gather the information
        )
        return count
@contextmanager
 def set_write_concern(collection, write_concerns):
    combined_concerns = dict(collection.write_concern.document.items())
    combined_concerns.update(write_concerns)
    yield collection.with_options(write_concern=WriteConcern(**combined_concerns))
@contextmanager
 def set_read_write_concern(collection, write_concerns, read_concerns):
    combined_write_concerns = dict(collection.write_concern.document.items())
    if write_concerns is not None:
        combined_write_concerns.update(write_concerns)
    combined_read_concerns = dict(collection.read_concern.document.items())
    if read_concerns is not None:
        combined_read_concerns.update(read_concerns)
    yield collection.with_options(
        write_concern=WriteConcern(**combined_write_concerns),
        read_concern=ReadConcern(**combined_read_concerns),
    )
--- a/mongoengine/dereference.py
+++ b/mongoengine/dereference.py
@ -1,29 +1,18 @@
-from bson import SON, DBRef
+from bson import DBRef, SON
-from mongoengine.base import (
+from base import (BaseDict, BaseList, TopLevelDocumentMetaclass, get_document)
-    BaseDict,
+from fields import (ReferenceField, ListField, DictField, MapField)
-    BaseList,
+from connection import get_db
-    EmbeddedDocumentList,
+from queryset import QuerySet
-    TopLevelDocumentMetaclass,
+from document import Document
    get_document,
 )
 from mongoengine.base.datastructures import LazyReference
 from mongoengine.connection import get_db
 from mongoengine.document import Document, EmbeddedDocument
 from mongoengine.fields import (
    DictField,
    ListField,
    MapField,
    ReferenceField,
 )
 from mongoengine.queryset import QuerySet
-class DeReference:
+class DeReference(object):
    def __call__(self, items, max_depth=1, instance=None, name=None):
        """
        Cheaply dereferences the items to a set depth.
-        Also handles the conversion of complex data types.
+        Also handles the convertion of complex data types.
        :param items: The iterable (dict, list, queryset) to be dereferenced.
        :param max_depth: The maximum depth to recurse to
@ -33,7 +22,7 @@ class DeReference:
            :class:`~mongoengine.base.ComplexBaseField`
        :param get: A boolean determining if being called by __get__
        """
-        if items is None or isinstance(items, str):
+        if items is None or isinstance(items, basestring):
            return items
        # cheapest way to convert a queryset to a list
@ -42,61 +31,34 @@ class DeReference:
            items = [i for i in items]
        self.max_depth = max_depth
        doc_type = None
-        if instance and isinstance(
+        doc_type = None
-            instance, (Document, EmbeddedDocument, TopLevelDocumentMetaclass)
+        if instance and instance._fields:
-        ):
+            doc_type = instance._fields[name]
-            doc_type = instance._fields.get(name)
+            if hasattr(doc_type, 'field'):
            while hasattr(doc_type, "field"):
                doc_type = doc_type.field
            if isinstance(doc_type, ReferenceField):
                field = doc_type
                doc_type = doc_type.document_type
-                is_list = not hasattr(items, "items")
+                is_list = not hasattr(items, 'items')
-                if is_list and all(i.__class__ == doc_type for i in items):
+                if is_list and all([i.__class__ == doc_type for i in items]):
                    return items
-                elif not is_list and all(
+                elif not is_list and all([i.__class__ == doc_type
-                    i.__class__ == doc_type for i in items.values()
+                                         for i in items.values()]):
                ):
                    return items
                elif not field.dbref:
-                    # We must turn the ObjectIds into DBRefs
+                    if not hasattr(items, 'items'):
-
+                        items = [field.to_python(v)
-                    # Recursively dig into the sub items of a list/dict
+                             if not isinstance(v, (DBRef, Document)) else v
-                    # to turn the ObjectIds into DBRefs
+                             for v in items]
                    def _get_items_from_list(items):
                        new_items = []
                        for v in items:
                            value = v
                            if isinstance(v, dict):
                                value = _get_items_from_dict(v)
                            elif isinstance(v, list):
                                value = _get_items_from_list(v)
                            elif not isinstance(v, (DBRef, Document)):
                                value = field.to_python(v)
                            new_items.append(value)
                        return new_items
                    def _get_items_from_dict(items):
                        new_items = {}
                        for k, v in items.items():
                            value = v
                            if isinstance(v, list):
                                value = _get_items_from_list(v)
                            elif isinstance(v, dict):
                                value = _get_items_from_dict(v)
                            elif not isinstance(v, (DBRef, Document)):
                                value = field.to_python(v)
                            new_items[k] = value
                        return new_items
                    if not hasattr(items, "items"):
                        items = _get_items_from_list(items)
                    else:
-                        items = _get_items_from_dict(items)
+                        items = dict([
                            (k, field.to_python(v))
                            if not isinstance(v, (DBRef, Document)) else (k, v)
                            for k, v in items.iteritems()]
                        )
        self.reference_map = self._find_references(items)
        self.object_map = self._fetch_objects(doc_type=doc_type)
@ -114,97 +76,68 @@ class DeReference:
            return reference_map
        # Determine the iterator to use
-        if isinstance(items, dict):
+        if not hasattr(items, 'items'):
-            iterator = items.values()
+            iterator = enumerate(items)
        else:
-            iterator = items
+            iterator = items.iteritems()
        # Recursively find dbreferences
        depth += 1
-        for item in iterator:
+        for k, item in iterator:
-            if isinstance(item, (Document, EmbeddedDocument)):
+            if hasattr(item, '_fields'):
-                for field_name, field in item._fields.items():
+                for field_name, field in item._fields.iteritems():
                    v = item._data.get(field_name, None)
-                    if isinstance(v, LazyReference):
+                    if isinstance(v, (DBRef)):
-                        # LazyReference inherits DBRef but should not be dereferenced here !
+                        reference_map.setdefault(field.document_type, []).append(v.id)
-                        continue
+                    elif isinstance(v, (dict, SON)) and '_ref' in v:
-                    elif isinstance(v, DBRef):
+                        reference_map.setdefault(get_document(v['_cls']), []).append(v['_ref'].id)
                        reference_map.setdefault(field.document_type, set()).add(v.id)
                    elif isinstance(v, (dict, SON)) and "_ref" in v:
                        reference_map.setdefault(get_document(v["_cls"]), set()).add(
                            v["_ref"].id
                        )
                    elif isinstance(v, (dict, list, tuple)) and depth <= self.max_depth:
-                        field_cls = getattr(
+                        field_cls = getattr(getattr(field, 'field', None), 'document_type', None)
                            getattr(field, "field", None), "document_type", None
                        )
                        references = self._find_references(v, depth)
-                        for key, refs in references.items():
+                        for key, refs in references.iteritems():
-                            if isinstance(
+                            if isinstance(field_cls, (Document, TopLevelDocumentMetaclass)):
                                field_cls, (Document, TopLevelDocumentMetaclass)
                            ):
                                key = field_cls
-                            reference_map.setdefault(key, set()).update(refs)
+                            reference_map.setdefault(key, []).extend(refs)
-            elif isinstance(item, LazyReference):
+            elif isinstance(item, (DBRef)):
-                # LazyReference inherits DBRef but should not be dereferenced here !
+                reference_map.setdefault(item.collection, []).append(item.id)
-                continue
+            elif isinstance(item, (dict, SON)) and '_ref' in item:
-            elif isinstance(item, DBRef):
+                reference_map.setdefault(get_document(item['_cls']), []).append(item['_ref'].id)
                reference_map.setdefault(item.collection, set()).add(item.id)
            elif isinstance(item, (dict, SON)) and "_ref" in item:
                reference_map.setdefault(get_document(item["_cls"]), set()).add(
                    item["_ref"].id
                )
            elif isinstance(item, (dict, list, tuple)) and depth - 1 <= self.max_depth:
                references = self._find_references(item, depth - 1)
-                for key, refs in references.items():
+                for key, refs in references.iteritems():
-                    reference_map.setdefault(key, set()).update(refs)
+                    reference_map.setdefault(key, []).extend(refs)
        return reference_map
    def _fetch_objects(self, doc_type=None):
-        """Fetch all references and convert to their document objects"""
+        """Fetch all references and convert to their document objects
        """
        object_map = {}
-        for collection, dbrefs in self.reference_map.items():
+        for col, dbrefs in self.reference_map.iteritems():
-
+            keys = object_map.keys()
-            # we use getattr instead of hasattr because hasattr swallows any exception under python2
+            refs = list(set([dbref for dbref in dbrefs if str(dbref) not in keys]))
-            # so it could hide nasty things without raising exceptions (cfr bug #1688))
+            if hasattr(col, 'objects'):  # We have a document class for the refs
-            ref_document_cls_exists = getattr(collection, "objects", None) is not None
+                references = col.objects.in_bulk(refs)
-
+                for key, doc in references.iteritems():
-            if ref_document_cls_exists:
+                    object_map[key] = doc
                col_name = collection._get_collection_name()
                refs = [
                    dbref for dbref in dbrefs if (col_name, dbref) not in object_map
                ]
                references = collection.objects.in_bulk(refs)
                for key, doc in references.items():
                    object_map[(col_name, key)] = doc
            else:  # Generic reference: use the refs data to convert to document
-                if isinstance(doc_type, (ListField, DictField, MapField)):
+                if doc_type and not isinstance(doc_type, (ListField, DictField, MapField,) ):
-                    continue
+                    references = doc_type._get_db()[col].find({'_id': {'$in': refs}})
                refs = [
                    dbref for dbref in dbrefs if (collection, dbref) not in object_map
                ]
                if doc_type:
                    references = doc_type._get_db()[collection].find(
                        {"_id": {"$in": refs}}
                    )
                    for ref in references:
                        doc = doc_type._from_son(ref)
-                        object_map[(collection, doc.id)] = doc
+                        object_map[doc.id] = doc
                else:
-                    references = get_db()[collection].find({"_id": {"$in": refs}})
+                    references = get_db()[col].find({'_id': {'$in': refs}})
                    for ref in references:
-                        if "_cls" in ref:
+                        if '_cls' in ref:
                            doc = get_document(ref["_cls"])._from_son(ref)
                        elif doc_type is None:
                            doc = get_document(
-                                "".join(x.capitalize() for x in collection.split("_"))
+                                ''.join(x.capitalize()
-                            )._from_son(ref)
+                                        for x in col.split('_')))._from_son(ref)
                        else:
                            doc = doc_type._from_son(ref)
-                        object_map[(collection, doc.id)] = doc
+                        object_map[doc.id] = doc
        return object_map
    def _attach_objects(self, items, depth=0, instance=None, name=None):
@ -229,30 +162,20 @@ class DeReference:
                    return BaseList(items, instance, name)
        if isinstance(items, (dict, SON)):
-            if "_ref" in items:
+            if '_ref' in items:
-                return self.object_map.get(
+                return self.object_map.get(items['_ref'].id, items)
-                    (items["_ref"].collection, items["_ref"].id), items
+            elif '_types' in items and '_cls' in items:
-                )
+                doc = get_document(items['_cls'])._from_son(items)
-            elif "_cls" in items:
+                doc._data = self._attach_objects(doc._data, depth, doc, name)
                doc = get_document(items["_cls"])._from_son(items)
                _cls = doc._data.pop("_cls", None)
                del items["_cls"]
                doc._data = self._attach_objects(doc._data, depth, doc, None)
                if _cls is not None:
                    doc._data["_cls"] = _cls
                return doc
-        if not hasattr(items, "items"):
+        if not hasattr(items, 'items'):
            is_list = True
            list_type = BaseList
            if isinstance(items, EmbeddedDocumentList):
                list_type = EmbeddedDocumentList
            as_tuple = isinstance(items, tuple)
            iterator = enumerate(items)
            data = []
        else:
            is_list = False
-            iterator = items.items()
+            iterator = items.iteritems()
            data = {}
        depth += 1
@ -264,33 +187,25 @@ class DeReference:
            if k in self.object_map and not is_list:
                data[k] = self.object_map[k]
-            elif isinstance(v, (Document, EmbeddedDocument)):
+            elif hasattr(v, '_fields'):
-                for field_name in v._fields:
+                for field_name, field in v._fields.iteritems():
                    v = data[k]._data.get(field_name, None)
-                    if isinstance(v, DBRef):
+                    if isinstance(v, (DBRef)):
-                        data[k]._data[field_name] = self.object_map.get(
+                        data[k]._data[field_name] = self.object_map.get(v.id, v)
-                            (v.collection, v.id), v
+                    elif isinstance(v, (dict, SON)) and '_ref' in v:
-                        )
+                        data[k]._data[field_name] = self.object_map.get(v['_ref'].id, v)
-                    elif isinstance(v, (dict, SON)) and "_ref" in v:
+                    elif isinstance(v, dict) and depth <= self.max_depth:
-                        data[k]._data[field_name] = self.object_map.get(
+                        data[k]._data[field_name] = self._attach_objects(v, depth, instance=instance, name=name)
-                            (v["_ref"].collection, v["_ref"].id), v
+                    elif isinstance(v, (list, tuple)) and depth <= self.max_depth:
-                        )
+                        data[k]._data[field_name] = self._attach_objects(v, depth, instance=instance, name=name)
                    elif isinstance(v, (dict, list, tuple)) and depth <= self.max_depth:
                        item_name = f"{name}.{k}.{field_name}"
                        data[k]._data[field_name] = self._attach_objects(
                            v, depth, instance=instance, name=item_name
                        )
            elif isinstance(v, (dict, list, tuple)) and depth <= self.max_depth:
-                item_name = f"{name}.{k}" if name else name
+                data[k] = self._attach_objects(v, depth - 1, instance=instance, name=name)
-                data[k] = self._attach_objects(
+            elif hasattr(v, 'id'):
-                    v, depth - 1, instance=instance, name=item_name
+                data[k] = self.object_map.get(v.id, v)
                )
            elif isinstance(v, DBRef) and hasattr(v, "id"):
                data[k] = self.object_map.get((v.collection, v.id), v)
        if instance and name:
            if is_list:
-                return tuple(data) if as_tuple else list_type(data, instance, name)
+                return BaseList(data, instance, name)
            return BaseDict(data, instance, name)
        depth += 1
        return data
--- a/mongoengine/django/init.py
+++ b/mongoengine/django/init.py
--- a/mongoengine/django/auth.py
+++ b/mongoengine/django/auth.py
@ -0,0 +1,159 @@
 import datetime
 from mongoengine import *
 from django.utils.encoding import smart_str
 from django.contrib.auth.models import AnonymousUser
 from django.utils.translation import ugettext_lazy as _
 try:
    from django.contrib.auth.hashers import check_password, make_password
 except ImportError:
    """Handle older versions of Django"""
    from django.utils.hashcompat import md5_constructor, sha_constructor
    def get_hexdigest(algorithm, salt, raw_password):
        raw_password, salt = smart_str(raw_password), smart_str(salt)
        if algorithm == 'md5':
            return md5_constructor(salt + raw_password).hexdigest()
        elif algorithm == 'sha1':
            return sha_constructor(salt + raw_password).hexdigest()
        raise ValueError('Got unknown password algorithm type in password')
    def check_password(raw_password, password):
        algo, salt, hash = password.split('$')
        return hash == get_hexdigest(algo, salt, raw_password)
    def make_password(raw_password):
        from random import random
        algo = 'sha1'
        salt = get_hexdigest(algo, str(random()), str(random()))[:5]
        hash = get_hexdigest(algo, salt, raw_password)
        return '%s$%s$%s' % (algo, salt, hash)
 REDIRECT_FIELD_NAME = 'next'
 class User(Document):
    """A User document that aims to mirror most of the API specified by Django
    at http://docs.djangoproject.com/en/dev/topics/auth/#users
    """
    username = StringField(max_length=30, required=True,
                           verbose_name=_('username'),
                           help_text=_("Required. 30 characters or fewer. Letters, numbers and @/./+/-/_ characters"))
    first_name = StringField(max_length=30,
                             verbose_name=_('first name'))
    last_name = StringField(max_length=30,
                            verbose_name=_('last name'))
    email = EmailField(verbose_name=_('e-mail address'))
    password = StringField(max_length=128,
                           verbose_name=_('password'),
                           help_text=_("Use '[algo]$[iterations]$[salt]$[hexdigest]' or use the <a href=\"password/\">change password form</a>."))
    is_staff = BooleanField(default=False,
                            verbose_name=_('staff status'),
                            help_text=_("Designates whether the user can log into this admin site."))
    is_active = BooleanField(default=True,
                             verbose_name=_('active'),
                             help_text=_("Designates whether this user should be treated as active. Unselect this instead of deleting accounts."))
    is_superuser = BooleanField(default=False,
                                verbose_name=_('superuser status'),
                                help_text=_("Designates that this user has all permissions without explicitly assigning them."))
    last_login = DateTimeField(default=datetime.datetime.now,
                               verbose_name=_('last login'))
    date_joined = DateTimeField(default=datetime.datetime.now,
                                verbose_name=_('date joined'))
    meta = {
        'allow_inheritance': True,
        'indexes': [
            {'fields': ['username'], 'unique': True}
        ]
    }
    def __unicode__(self):
        return self.username
    def get_full_name(self):
        """Returns the users first and last names, separated by a space.
        """
        full_name = u'%s %s' % (self.first_name or '', self.last_name or '')
        return full_name.strip()
    def is_anonymous(self):
        return False
    def is_authenticated(self):
        return True
    def set_password(self, raw_password):
        """Sets the user's password - always use this rather than directly
        assigning to :attr:`~mongoengine.django.auth.User.password` as the
        password is hashed before storage.
        """
        self.password = make_password(raw_password)
        self.save()
        return self
    def check_password(self, raw_password):
        """Checks the user's password against a provided password - always use
        this rather than directly comparing to
        :attr:`~mongoengine.django.auth.User.password` as the password is
        hashed before storage.
        """
        return check_password(raw_password, self.password)
    @classmethod
    def create_user(cls, username, password, email=None):
        """Create (and save) a new user with the given username, password and
        email address.
        """
        now = datetime.datetime.now()
        # Normalize the address by lowercasing the domain part of the email
        # address.
        if email is not None:
            try:
                email_name, domain_part = email.strip().split('@', 1)
            except ValueError:
                pass
            else:
                email = '@'.join([email_name, domain_part.lower()])
        user = cls(username=username, email=email, date_joined=now)
        user.set_password(password)
        user.save()
        return user
    def get_and_delete_messages(self):
        return []
 class MongoEngineBackend(object):
    """Authenticate using MongoEngine and mongoengine.django.auth.User.
    """
    supports_object_permissions = False
    supports_anonymous_user = False
    supports_inactive_user = False
    def authenticate(self, username=None, password=None):
        user = User.objects(username=username).first()
        if user:
            if password and user.check_password(password):
                return user
        return None
    def get_user(self, user_id):
        return User.objects.with_id(user_id)
 def get_user(userid):
    """Returns a User object from an id (User.id). Django's equivalent takes
    request, but taking an id instead leaves it up to the developer to store
    the id in any way they want (session, signed cookie, etc.)
    """
    if not userid:
        return AnonymousUser()
    return MongoEngineBackend().get_user(userid) or AnonymousUser()
--- a/mongoengine/django/sessions.py
+++ b/mongoengine/django/sessions.py
@ -0,0 +1,74 @@
 from datetime import datetime
 from django.conf import settings
 from django.contrib.sessions.backends.base import SessionBase, CreateError
 from django.core.exceptions import SuspiciousOperation
 from django.utils.encoding import force_unicode
 from mongoengine.document import Document
 from mongoengine import fields
 from mongoengine.queryset import OperationError
 from mongoengine.connection import DEFAULT_CONNECTION_NAME
 MONGOENGINE_SESSION_DB_ALIAS = getattr(
    settings, 'MONGOENGINE_SESSION_DB_ALIAS',
    DEFAULT_CONNECTION_NAME)
 class MongoSession(Document):
    session_key = fields.StringField(primary_key=True, max_length=40)
    session_data = fields.StringField()
    expire_date = fields.DateTimeField()
    meta = {'collection': 'django_session',
            'db_alias': MONGOENGINE_SESSION_DB_ALIAS,
            'allow_inheritance': False}
 class SessionStore(SessionBase):
    """A MongoEngine-based session store for Django.
    """
    def load(self):
        try:
            s = MongoSession.objects(session_key=self.session_key,
                                     expire_date__gt=datetime.now())[0]
            return self.decode(force_unicode(s.session_data))
        except (IndexError, SuspiciousOperation):
            self.create()
            return {}
    def exists(self, session_key):
        return bool(MongoSession.objects(session_key=session_key).first())
    def create(self):
        while True:
            self._session_key = self._get_new_session_key()
            try:
                self.save(must_create=True)
            except CreateError:
                continue
            self.modified = True
            self._session_cache = {}
            return
    def save(self, must_create=False):
        if self.session_key is None:
            self._session_key = self._get_new_session_key()
        s = MongoSession(session_key=self.session_key)
        s.session_data = self.encode(self._get_session(no_load=must_create))
        s.expire_date = self.get_expiry_date()
        try:
            s.save(force_insert=must_create, safe=True)
        except OperationError:
            if must_create:
                raise CreateError
            raise
    def delete(self, session_key=None):
        if session_key is None:
            if self.session_key is None:
                return
            session_key = self.session_key
        MongoSession.objects(session_key=session_key).delete()
--- a/mongoengine/django/shortcuts.py
+++ b/mongoengine/django/shortcuts.py
@ -0,0 +1,47 @@
 from mongoengine.queryset import QuerySet
 from mongoengine.base import BaseDocument
 from mongoengine.base import ValidationError
 def _get_queryset(cls):
    """Inspired by django.shortcuts.*"""
    if isinstance(cls, QuerySet):
        return cls
    else:
        return cls.objects
 def get_document_or_404(cls, *args, **kwargs):
    """
    Uses get() to return an document, or raises a Http404 exception if the document
    does not exist.
    cls may be a Document or QuerySet object. All other passed
    arguments and keyword arguments are used in the get() query.
    Note: Like with get(), an MultipleObjectsReturned will be raised if more than one
    object is found.
    Inspired by django.shortcuts.*
    """
    queryset = _get_queryset(cls)
    try:
        return queryset.get(*args, **kwargs)
    except (queryset._document.DoesNotExist, ValidationError):
        from django.http import Http404
        raise Http404('No %s matches the given query.' % queryset._document._class_name)
 def get_list_or_404(cls, *args, **kwargs):
    """
    Uses filter() to return a list of documents, or raise a Http404 exception if
    the list is empty.
    cls may be a Document or QuerySet object. All other passed
    arguments and keyword arguments are used in the filter() query.
    Inspired by django.shortcuts.*
    """
    queryset = _get_queryset(cls)
    obj_list = list(queryset.filter(*args, **kwargs))
    if not obj_list:
        from django.http import Http404
        raise Http404('No %s matches the given query.' % queryset._document._class_name)
    return obj_list
--- a/mongoengine/django/storage.py
+++ b/mongoengine/django/storage.py
@ -0,0 +1,112 @@
 import os
 import itertools
 import urlparse
 from mongoengine import *
 from django.conf import settings
 from django.core.files.storage import Storage
 from django.core.exceptions import ImproperlyConfigured
 class FileDocument(Document):
    """A document used to store a single file in GridFS.
    """
    file = FileField()
 class GridFSStorage(Storage):
    """A custom storage backend to store files in GridFS
    """
    def __init__(self, base_url=None):
        if base_url is None:
            base_url = settings.MEDIA_URL
        self.base_url = base_url
        self.document = FileDocument
        self.field = 'file'
    def delete(self, name):
        """Deletes the specified file from the storage system.
        """
        if self.exists(name):
            doc = self.document.objects.first()
            field = getattr(doc, self.field)
            self._get_doc_with_name(name).delete()  # Delete the FileField
            field.delete()                          # Delete the FileDocument
    def exists(self, name):
        """Returns True if a file referened by the given name already exists in the
        storage system, or False if the name is available for a new file.
        """
        doc = self._get_doc_with_name(name)
        if doc:
            field = getattr(doc, self.field)
            return bool(field.name)
        else:
            return False
    def listdir(self, path=None):
        """Lists the contents of the specified path, returning a 2-tuple of lists;
        the first item being directories, the second item being files.
        """
        def name(doc):
            return getattr(doc, self.field).name
        docs = self.document.objects
        return [], [name(d) for d in docs if name(d)]
    def size(self, name):
        """Returns the total size, in bytes, of the file specified by name.
        """
        doc = self._get_doc_with_name(name)
        if doc:
            return getattr(doc, self.field).length
        else:
            raise ValueError("No such file or directory: '%s'" % name)
    def url(self, name):
        """Returns an absolute URL where the file's contents can be accessed
        directly by a web browser.
        """
        if self.base_url is None:
            raise ValueError("This file is not accessible via a URL.")
        return urlparse.urljoin(self.base_url, name).replace('\\', '/')
    def _get_doc_with_name(self, name):
        """Find the documents in the store with the given name
        """
        docs = self.document.objects
        doc = [d for d in docs if getattr(d, self.field).name == name]
        if doc:
            return doc[0]
        else:
            return None
    def _open(self, name, mode='rb'):
        doc = self._get_doc_with_name(name)
        if doc:
            return getattr(doc, self.field)
        else:
            raise ValueError("No file found with the name '%s'." % name)
    def get_available_name(self, name):
        """Returns a filename that's free on the target storage system, and
        available for new content to be written to.
        """
        file_root, file_ext = os.path.splitext(name)
        # If the filename already exists, add an underscore and a number (before
        # the file extension, if one exists) to the filename until the generated
        # filename doesn't exist.
        count = itertools.count(1)
        while self.exists(name):
            # file_ext includes the dot.
            name = os.path.join("%s_%s%s" % (file_root, count.next(), file_ext))
        return name
    def _save(self, name, content):
        doc = self.document()
        getattr(doc, self.field).put(content, filename=name)
        doc.save()
        return name
--- a/mongoengine/django/tests.py
+++ b/mongoengine/django/tests.py
@ -0,0 +1,39 @@
 #coding: utf-8
 from nose.plugins.skip import SkipTest
 from mongoengine.python_support import PY3
 from mongoengine import connect
 try:
    from django.test import TestCase
    from django.conf import settings
 except Exception as err:
    if PY3:
        from unittest import TestCase
        # Dummy value so no error
        class settings:
            MONGO_DATABASE_NAME = 'dummy'
    else:
        raise err
 class MongoTestCase(TestCase):
    def setUp(self):
        if PY3:
            raise SkipTest('django does not have Python 3 support')
    """
    TestCase class that clear the collection between the tests
    """
    db_name = 'test_%s' % settings.MONGO_DATABASE_NAME
    def __init__(self, methodName='runtest'):
        self.db = connect(self.db_name).get_db()
        super(MongoTestCase, self).__init__(methodName)
    def _post_teardown(self):
        super(MongoTestCase, self)._post_teardown()
        for collection in self.db.collection_names():
            if collection == 'system.indexes':
                continue
            self.db.drop_collection(collection)
--- a/mongoengine/document.py
+++ b/mongoengine/document.py
--- a/mongoengine/errors.py
+++ b/mongoengine/errors.py
@ -1,165 +0,0 @@
 from collections import defaultdict
 __all__ = (
    "NotRegistered",
    "InvalidDocumentError",
    "LookUpError",
    "DoesNotExist",
    "MultipleObjectsReturned",
    "InvalidQueryError",
    "OperationError",
    "NotUniqueError",
    "BulkWriteError",
    "FieldDoesNotExist",
    "ValidationError",
    "SaveConditionError",
    "DeprecatedError",
 )
 class MongoEngineException(Exception):
    pass
 class NotRegistered(MongoEngineException):
    pass
 class InvalidDocumentError(MongoEngineException):
    pass
 class LookUpError(AttributeError):
    pass
 class DoesNotExist(MongoEngineException):
    pass
 class MultipleObjectsReturned(MongoEngineException):
    pass
 class InvalidQueryError(MongoEngineException):
    pass
 class OperationError(MongoEngineException):
    pass
 class NotUniqueError(OperationError):
    pass
 class BulkWriteError(OperationError):
    pass
 class SaveConditionError(OperationError):
    pass
 class FieldDoesNotExist(MongoEngineException):
    """Raised when trying to set a field
    not declared in a :class:`~mongoengine.Document`
    or an :class:`~mongoengine.EmbeddedDocument`.
    To avoid this behavior on data loading,
    you should set the :attr:`strict` to ``False``
    in the :attr:`meta` dictionary.
    """
 class ValidationError(AssertionError):
    """Validation exception.
    May represent an error validating a field or a
    document containing fields with validation errors.
    :ivar errors: A dictionary of errors for fields within this
        document or list, or None if the error is for an
        individual field.
    """
    errors = {}
    field_name = None
    _message = None
    def __init__(self, message="", **kwargs):
        super().__init__(message)
        self.errors = kwargs.get("errors", {})
        self.field_name = kwargs.get("field_name")
        self.message = message
    def __str__(self):
        return str(self.message)
    def __repr__(self):
        return f"{self.__class__.__name__}({self.message},)"
    def __getattribute__(self, name):
        message = super().__getattribute__(name)
        if name == "message":
            if self.field_name:
                message = "%s" % message
            if self.errors:
                message = f"{message}({self._format_errors()})"
        return message
    def _get_message(self):
        return self._message
    def _set_message(self, message):
        self._message = message
    message = property(_get_message, _set_message)
    def to_dict(self):
        """Returns a dictionary of all errors within a document
        Keys are field names or list indices and values are the
        validation error messages, or a nested dictionary of
        errors for an embedded document or list.
        """
        def build_dict(source):
            errors_dict = {}
            if isinstance(source, dict):
                for field_name, error in source.items():
                    errors_dict[field_name] = build_dict(error)
            elif isinstance(source, ValidationError) and source.errors:
                return build_dict(source.errors)
            else:
                return str(source)
            return errors_dict
        if not self.errors:
            return {}
        return build_dict(self.errors)
    def _format_errors(self):
        """Returns a string listing all errors within a document"""
        def generate_key(value, prefix=""):
            if isinstance(value, list):
                value = " ".join([generate_key(k) for k in value])
            elif isinstance(value, dict):
                value = " ".join([generate_key(v, k) for k, v in value.items()])
            results = f"{prefix}.{value}" if prefix else value
            return results
        error_dict = defaultdict(list)
        for k, v in self.to_dict().items():
            error_dict[generate_key(v)].append(k)
        return " ".join([f"{k}: {v}" for k, v in error_dict.items()])
 class DeprecatedError(MongoEngineException):
    """Raise when a user uses a feature that has been Deprecated"""
    pass
--- a/mongoengine/fields.py
+++ b/mongoengine/fields.py
--- a/mongoengine/mongodb_support.py
+++ b/mongoengine/mongodb_support.py
@ -1,20 +0,0 @@
 """
 Helper functions, constants, and types to aid with MongoDB version support
 """
 from mongoengine.connection import get_connection
 # Constant that can be used to compare the version retrieved with
 # get_mongodb_version()
 MONGODB_34 = (3, 4)
 MONGODB_36 = (3, 6)
 MONGODB_42 = (4, 2)
 MONGODB_44 = (4, 4)
 def get_mongodb_version():
    """Return the version of the default connected mongoDB (first 2 digits)
    :return: tuple(int, int)
    """
    version_list = get_connection().server_info()["versionArray"][:2]  # e.g: (3, 2)
    return tuple(version_list)
--- a/mongoengine/pymongo_support.py
+++ b/mongoengine/pymongo_support.py
@ -1,60 +0,0 @@
 """
 Helper functions, constants, and types to aid with PyMongo v2.7 - v3.x support.
 """
 import pymongo
 from pymongo.errors import OperationFailure
 _PYMONGO_37 = (3, 7)
 PYMONGO_VERSION = tuple(pymongo.version_tuple[:2])
 IS_PYMONGO_GTE_37 = PYMONGO_VERSION >= _PYMONGO_37
 def count_documents(
    collection, filter, skip=None, limit=None, hint=None, collation=None
 ):
    """Pymongo>3.7 deprecates count in favour of count_documents"""
    if limit == 0:
        return 0  # Pymongo raises an OperationFailure if called with limit=0
    kwargs = {}
    if skip is not None:
        kwargs["skip"] = skip
    if limit is not None:
        kwargs["limit"] = limit
    if hint not in (-1, None):
        kwargs["hint"] = hint
    if collation is not None:
        kwargs["collation"] = collation
    # count_documents appeared in pymongo 3.7
    if IS_PYMONGO_GTE_37:
        try:
            return collection.count_documents(filter=filter, **kwargs)
        except OperationFailure:
            # OperationFailure - accounts for some operators that used to work
            # with .count but are no longer working with count_documents (i.e $geoNear, $near, and $nearSphere)
            # fallback to deprecated Cursor.count
            # Keeping this should be reevaluated the day pymongo removes .count entirely
            pass
    cursor = collection.find(filter)
    for option, option_value in kwargs.items():
        cursor_method = getattr(cursor, option)
        cursor = cursor_method(option_value)
    with_limit_and_skip = "skip" in kwargs or "limit" in kwargs
    return cursor.count(with_limit_and_skip=with_limit_and_skip)
 def list_collection_names(db, include_system_collections=False):
    """Pymongo>3.7 deprecates collection_names in favour of list_collection_names"""
    if IS_PYMONGO_GTE_37:
        collections = db.list_collection_names()
    else:
        collections = db.collection_names()
    if not include_system_collections:
        collections = [c for c in collections if not c.startswith("system.")]
    return collections
--- a/mongoengine/python_support.py
+++ b/mongoengine/python_support.py
@ -0,0 +1,60 @@
 """Helper functions and types to aid with Python 2.5 - 3 support."""
 import sys
 PY3 = sys.version_info[0] == 3
 PY25 = sys.version_info[:2] == (2, 5)
 if PY3:
    import codecs
    from io import BytesIO as StringIO
    # return s converted to binary.  b('test') should be equivalent to b'test'
    def b(s):
        return codecs.latin_1_encode(s)[0]
    bin_type = bytes
    txt_type   = str
 else:
    try:
        from cStringIO import StringIO
    except ImportError:
        from StringIO import StringIO
    # Conversion to binary only necessary in Python 3
    def b(s):
        return s
    bin_type = str
    txt_type = unicode
 str_types = (bin_type, txt_type)
 if PY25:
    def product(*args, **kwds):
        pools = map(tuple, args) * kwds.get('repeat', 1)
        result = [[]]
        for pool in pools:
            result = [x + [y] for x in result for y in pool]
        for prod in result:
            yield tuple(prod)
    reduce = reduce
 else:
    from itertools import product
    from functools import reduce
 # For use with Python 2.5
 # converts all keys from unicode to str for d and all nested dictionaries
 def to_str_keys_recursive(d):
    if isinstance(d, list):
        for val in d:
            if isinstance(val, (dict, list)):
                to_str_keys_recursive(val)
    elif isinstance(d, dict):
        for key, val in d.items():
            if isinstance(val, (dict, list)):
                to_str_keys_recursive(val)
            if isinstance(key, unicode):
                d[str(key)] = d.pop(key)
    else:
        raise ValueError("non list/dict parameter not allowed")
--- a/mongoengine/queryset.py
+++ b/mongoengine/queryset.py
--- a/mongoengine/queryset/init.py
+++ b/mongoengine/queryset/init.py
@ -1,28 +0,0 @@
 from mongoengine.errors import *
 from mongoengine.queryset.field_list import *
 from mongoengine.queryset.manager import *
 from mongoengine.queryset.queryset import *
 from mongoengine.queryset.transform import *
 from mongoengine.queryset.visitor import *
 # Expose just the public subset of all imported objects and constants.
 __all__ = (
    "QuerySet",
    "QuerySetNoCache",
    "Q",
    "queryset_manager",
    "QuerySetManager",
    "QueryFieldList",
    "DO_NOTHING",
    "NULLIFY",
    "CASCADE",
    "DENY",
    "PULL",
    # Errors that might be related to a queryset, mostly here for backward
    # compatibility
    "DoesNotExist",
    "InvalidQueryError",
    "MultipleObjectsReturned",
    "NotUniqueError",
    "OperationError",
 )
--- a/mongoengine/queryset/base.py
+++ b/mongoengine/queryset/base.py
--- a/mongoengine/queryset/field_list.py
+++ b/mongoengine/queryset/field_list.py
@ -1,88 +0,0 @@
 __all__ = ("QueryFieldList",)
 class QueryFieldList:
    """Object that handles combinations of .only() and .exclude() calls"""
    ONLY = 1
    EXCLUDE = 0
    def __init__(
        self, fields=None, value=ONLY, always_include=None, _only_called=False
    ):
        """The QueryFieldList builder
        :param fields: A list of fields used in `.only()` or `.exclude()`
        :param value: How to handle the fields; either `ONLY` or `EXCLUDE`
        :param always_include: Any fields to always_include eg `_cls`
        :param _only_called: Has `.only()` been called?  If so its a set of fields
           otherwise it performs a union.
        """
        self.value = value
        self.fields = set(fields or [])
        self.always_include = set(always_include or [])
        self._id = None
        self._only_called = _only_called
        self.slice = {}
    def __add__(self, f):
        if isinstance(f.value, dict):
            for field in f.fields:
                self.slice[field] = f.value
            if not self.fields:
                self.fields = f.fields
        elif not self.fields:
            self.fields = f.fields
            self.value = f.value
            self.slice = {}
        elif self.value is self.ONLY and f.value is self.ONLY:
            self._clean_slice()
            if self._only_called:
                self.fields = self.fields.union(f.fields)
            else:
                self.fields = f.fields
        elif self.value is self.EXCLUDE and f.value is self.EXCLUDE:
            self.fields = self.fields.union(f.fields)
            self._clean_slice()
        elif self.value is self.ONLY and f.value is self.EXCLUDE:
            self.fields -= f.fields
            self._clean_slice()
        elif self.value is self.EXCLUDE and f.value is self.ONLY:
            self.value = self.ONLY
            self.fields = f.fields - self.fields
            self._clean_slice()
        if "_id" in f.fields:
            self._id = f.value
        if self.always_include:
            if self.value is self.ONLY and self.fields:
                if sorted(self.slice.keys()) != sorted(self.fields):
                    self.fields = self.fields.union(self.always_include)
            else:
                self.fields -= self.always_include
        if getattr(f, "_only_called", False):
            self._only_called = True
        return self
    def __bool__(self):
        return bool(self.fields)
    def as_dict(self):
        field_list = {field: self.value for field in self.fields}
        if self.slice:
            field_list.update(self.slice)
        if self._id is not None:
            field_list["_id"] = self._id
        return field_list
    def reset(self):
        self.fields = set()
        self.slice = {}
        self.value = self.ONLY
    def _clean_slice(self):
        if self.slice:
            for field in set(self.slice.keys()) - self.fields:
                del self.slice[field]
--- a/mongoengine/queryset/manager.py
+++ b/mongoengine/queryset/manager.py
@ -1,58 +0,0 @@
 from functools import partial
 from mongoengine.queryset.queryset import QuerySet
 __all__ = ("queryset_manager", "QuerySetManager")
 class QuerySetManager:
    """
    The default QuerySet Manager.
    Custom QuerySet Manager functions can extend this class and users can
    add extra queryset functionality.  Any custom manager methods must accept a
    :class:`~mongoengine.Document` class as its first argument, and a
    :class:`~mongoengine.queryset.QuerySet` as its second argument.
    The method function should return a :class:`~mongoengine.queryset.QuerySet`
    , probably the same one that was passed in, but modified in some way.
    """
    get_queryset = None
    default = QuerySet
    def __init__(self, queryset_func=None):
        if queryset_func:
            self.get_queryset = queryset_func
    def __get__(self, instance, owner):
        """Descriptor for instantiating a new QuerySet object when
        Document.objects is accessed.
        """
        if instance is not None:
            # Document object being used rather than a document class
            return self
        # owner is the document that contains the QuerySetManager
        queryset_class = owner._meta.get("queryset_class", self.default)
        queryset = queryset_class(owner, owner._get_collection())
        if self.get_queryset:
            arg_count = self.get_queryset.__code__.co_argcount
            if arg_count == 1:
                queryset = self.get_queryset(queryset)
            elif arg_count == 2:
                queryset = self.get_queryset(owner, queryset)
            else:
                queryset = partial(self.get_queryset, owner, queryset)
        return queryset
 def queryset_manager(func):
    """Decorator that allows you to define custom QuerySet managers on
    :class:`~mongoengine.Document` classes. The manager must be a function that
    accepts a :class:`~mongoengine.Document` class as its first argument, and a
    :class:`~mongoengine.queryset.QuerySet` as its second argument. The method
    function should return a :class:`~mongoengine.queryset.QuerySet`, probably
    the same one that was passed in, but modified in some way.
    """
    return QuerySetManager(func)
--- a/mongoengine/queryset/queryset.py
+++ b/mongoengine/queryset/queryset.py
@ -1,190 +0,0 @@
 from mongoengine.errors import OperationError
 from mongoengine.queryset.base import (
    CASCADE,
    DENY,
    DO_NOTHING,
    NULLIFY,
    PULL,
    BaseQuerySet,
 )
 __all__ = (
    "QuerySet",
    "QuerySetNoCache",
    "DO_NOTHING",
    "NULLIFY",
    "CASCADE",
    "DENY",
    "PULL",
 )
 # The maximum number of items to display in a QuerySet.__repr__
 REPR_OUTPUT_SIZE = 20
 ITER_CHUNK_SIZE = 100
 class QuerySet(BaseQuerySet):
    """The default queryset, that builds queries and handles a set of results
    returned from a query.
    Wraps a MongoDB cursor, providing :class:`~mongoengine.Document` objects as
    the results.
    """
    _has_more = True
    _len = None
    _result_cache = None
    def __iter__(self):
        """Iteration utilises a results cache which iterates the cursor
        in batches of ``ITER_CHUNK_SIZE``.
        If ``self._has_more`` the cursor hasn't been exhausted so cache then
        batch. Otherwise iterate the result_cache.
        """
        self._iter = True
        if self._has_more:
            return self._iter_results()
        # iterating over the cache.
        return iter(self._result_cache)
    def __len__(self):
        """Since __len__ is called quite frequently (for example, as part of
        list(qs)), we populate the result cache and cache the length.
        """
        if self._len is not None:
            return self._len
        # Populate the result cache with *all* of the docs in the cursor
        if self._has_more:
            list(self._iter_results())
        # Cache the length of the complete result cache and return it
        self._len = len(self._result_cache)
        return self._len
    def __repr__(self):
        """Provide a string representation of the QuerySet"""
        if self._iter:
            return ".. queryset mid-iteration .."
        self._populate_cache()
        data = self._result_cache[: REPR_OUTPUT_SIZE + 1]
        if len(data) > REPR_OUTPUT_SIZE:
            data[-1] = "...(remaining elements truncated)..."
        return repr(data)
    def _iter_results(self):
        """A generator for iterating over the result cache.
        Also populates the cache if there are more possible results to
        yield. Raises StopIteration when there are no more results.
        """
        if self._result_cache is None:
            self._result_cache = []
        pos = 0
        while True:
            # For all positions lower than the length of the current result
            # cache, serve the docs straight from the cache w/o hitting the
            # database.
            # XXX it's VERY important to compute the len within the `while`
            # condition because the result cache might expand mid-iteration
            # (e.g. if we call len(qs) inside a loop that iterates over the
            # queryset). Fortunately len(list) is O(1) in Python, so this
            # doesn't cause performance issues.
            while pos < len(self._result_cache):
                yield self._result_cache[pos]
                pos += 1
            # return if we already established there were no more
            # docs in the db cursor.
            if not self._has_more:
                return
            # Otherwise, populate more of the cache and repeat.
            if len(self._result_cache) <= pos:
                self._populate_cache()
    def _populate_cache(self):
        """
        Populates the result cache with ``ITER_CHUNK_SIZE`` more entries
        (until the cursor is exhausted).
        """
        if self._result_cache is None:
            self._result_cache = []
        # Skip populating the cache if we already established there are no
        # more docs to pull from the database.
        if not self._has_more:
            return
        # Pull in ITER_CHUNK_SIZE docs from the database and store them in
        # the result cache.
        try:
            for _ in range(ITER_CHUNK_SIZE):
                self._result_cache.append(next(self))
        except StopIteration:
            # Getting this exception means there are no more docs in the
            # db cursor. Set _has_more to False so that we can use that
            # information in other places.
            self._has_more = False
    def count(self, with_limit_and_skip=False):
        """Count the selected elements in the query.
        :param with_limit_and_skip (optional): take any :meth:`limit` or
            :meth:`skip` that has been applied to this cursor into account when
            getting the count
        """
        if with_limit_and_skip is False:
            return super().count(with_limit_and_skip)
        if self._len is None:
            # cache the length
            self._len = super().count(with_limit_and_skip)
        return self._len
    def no_cache(self):
        """Convert to a non-caching queryset"""
        if self._result_cache is not None:
            raise OperationError("QuerySet already cached")
        return self._clone_into(QuerySetNoCache(self._document, self._collection))
 class QuerySetNoCache(BaseQuerySet):
    """A non caching QuerySet"""
    def cache(self):
        """Convert to a caching queryset"""
        return self._clone_into(QuerySet(self._document, self._collection))
    def __repr__(self):
        """Provides the string representation of the QuerySet"""
        if self._iter:
            return ".. queryset mid-iteration .."
        data = []
        for _ in range(REPR_OUTPUT_SIZE + 1):
            try:
                data.append(next(self))
            except StopIteration:
                break
        if len(data) > REPR_OUTPUT_SIZE:
            data[-1] = "...(remaining elements truncated)..."
        self.rewind()
        return repr(data)
    def __iter__(self):
        queryset = self
        if queryset._iter:
            queryset = self.clone()
        queryset.rewind()
        return queryset
--- a/mongoengine/queryset/transform.py
+++ b/mongoengine/queryset/transform.py
@ -1,506 +0,0 @@
 from collections import defaultdict
 import pymongo
 from bson import SON, ObjectId
 from bson.dbref import DBRef
 from mongoengine.base import UPDATE_OPERATORS
 from mongoengine.common import _import_class
 from mongoengine.errors import InvalidQueryError
 __all__ = ("query", "update", "STRING_OPERATORS")
 COMPARISON_OPERATORS = (
    "ne",
    "gt",
    "gte",
    "lt",
    "lte",
    "in",
    "nin",
    "mod",
    "all",
    "size",
    "exists",
    "not",
    "elemMatch",
    "type",
 )
 GEO_OPERATORS = (
    "within_distance",
    "within_spherical_distance",
    "within_box",
    "within_polygon",
    "near",
    "near_sphere",
    "max_distance",
    "min_distance",
    "geo_within",
    "geo_within_box",
    "geo_within_polygon",
    "geo_within_center",
    "geo_within_sphere",
    "geo_intersects",
 )
 STRING_OPERATORS = (
    "contains",
    "icontains",
    "startswith",
    "istartswith",
    "endswith",
    "iendswith",
    "exact",
    "iexact",
    "regex",
    "iregex",
    "wholeword",
    "iwholeword",
 )
 CUSTOM_OPERATORS = ("match",)
 MATCH_OPERATORS = (
    COMPARISON_OPERATORS + GEO_OPERATORS + STRING_OPERATORS + CUSTOM_OPERATORS
 )
 # TODO make this less complex
 def query(_doc_cls=None, **kwargs):
    """Transform a query from Django-style format to Mongo format."""
    mongo_query = {}
    merge_query = defaultdict(list)
    for key, value in sorted(kwargs.items()):
        if key == "__raw__":
            mongo_query.update(value)
            continue
        parts = key.rsplit("__")
        indices = [(i, p) for i, p in enumerate(parts) if p.isdigit()]
        parts = [part for part in parts if not part.isdigit()]
        # Check for an operator and transform to mongo-style if there is
        op = None
        if len(parts) > 1 and parts[-1] in MATCH_OPERATORS:
            op = parts.pop()
        # Allow to escape operator-like field name by __
        if len(parts) > 1 and parts[-1] == "":
            parts.pop()
        negate = False
        if len(parts) > 1 and parts[-1] == "not":
            parts.pop()
            negate = True
        if _doc_cls:
            # Switch field names to proper names [set in Field(name='foo')]
            try:
                fields = _doc_cls._lookup_field(parts)
            except Exception as e:
                raise InvalidQueryError(e)
            parts = []
            CachedReferenceField = _import_class("CachedReferenceField")
            GenericReferenceField = _import_class("GenericReferenceField")
            cleaned_fields = []
            for field in fields:
                append_field = True
                if isinstance(field, str):
                    parts.append(field)
                    append_field = False
                # is last and CachedReferenceField
                elif isinstance(field, CachedReferenceField) and fields[-1] == field:
                    parts.append("%s._id" % field.db_field)
                else:
                    parts.append(field.db_field)
                if append_field:
                    cleaned_fields.append(field)
            # Convert value to proper value
            field = cleaned_fields[-1]
            singular_ops = [None, "ne", "gt", "gte", "lt", "lte", "not"]
            singular_ops += STRING_OPERATORS
            if op in singular_ops:
                value = field.prepare_query_value(op, value)
                if isinstance(field, CachedReferenceField) and value:
                    value = value["_id"]
            elif op in ("in", "nin", "all", "near") and not isinstance(value, dict):
                # Raise an error if the in/nin/all/near param is not iterable.
                value = _prepare_query_for_iterable(field, op, value)
            # If we're querying a GenericReferenceField, we need to alter the
            # key depending on the value:
            # * If the value is a DBRef, the key should be "field_name._ref".
            # * If the value is an ObjectId, the key should be "field_name._ref.$id".
            if isinstance(field, GenericReferenceField):
                if isinstance(value, DBRef):
                    parts[-1] += "._ref"
                elif isinstance(value, ObjectId):
                    parts[-1] += "._ref.$id"
        # if op and op not in COMPARISON_OPERATORS:
        if op:
            if op in GEO_OPERATORS:
                value = _geo_operator(field, op, value)
            elif op in ("match", "elemMatch"):
                ListField = _import_class("ListField")
                EmbeddedDocumentField = _import_class("EmbeddedDocumentField")
                if (
                    isinstance(value, dict)
                    and isinstance(field, ListField)
                    and isinstance(field.field, EmbeddedDocumentField)
                ):
                    value = query(field.field.document_type, **value)
                else:
                    value = field.prepare_query_value(op, value)
                value = {"$elemMatch": value}
            elif op in CUSTOM_OPERATORS:
                NotImplementedError(
                    'Custom method "%s" has not ' "been implemented" % op
                )
            elif op not in STRING_OPERATORS:
                value = {"$" + op: value}
        if negate:
            value = {"$not": value}
        for i, part in indices:
            parts.insert(i, part)
        key = ".".join(parts)
        if key not in mongo_query:
            mongo_query[key] = value
        else:
            if isinstance(mongo_query[key], dict) and isinstance(value, dict):
                mongo_query[key].update(value)
                # $max/minDistance needs to come last - convert to SON
                value_dict = mongo_query[key]
                if ("$maxDistance" in value_dict or "$minDistance" in value_dict) and (
                    "$near" in value_dict or "$nearSphere" in value_dict
                ):
                    value_son = SON()
                    for k, v in value_dict.items():
                        if k == "$maxDistance" or k == "$minDistance":
                            continue
                        value_son[k] = v
                    # Required for MongoDB >= 2.6, may fail when combining
                    # PyMongo 3+ and MongoDB < 2.6
                    near_embedded = False
                    for near_op in ("$near", "$nearSphere"):
                        if isinstance(value_dict.get(near_op), dict):
                            value_son[near_op] = SON(value_son[near_op])
                            if "$maxDistance" in value_dict:
                                value_son[near_op]["$maxDistance"] = value_dict[
                                    "$maxDistance"
                                ]
                            if "$minDistance" in value_dict:
                                value_son[near_op]["$minDistance"] = value_dict[
                                    "$minDistance"
                                ]
                            near_embedded = True
                    if not near_embedded:
                        if "$maxDistance" in value_dict:
                            value_son["$maxDistance"] = value_dict["$maxDistance"]
                        if "$minDistance" in value_dict:
                            value_son["$minDistance"] = value_dict["$minDistance"]
                    mongo_query[key] = value_son
            else:
                # Store for manually merging later
                merge_query[key].append(value)
    # The queryset has been filter in such a way we must manually merge
    for k, v in merge_query.items():
        merge_query[k].append(mongo_query[k])
        del mongo_query[k]
        if isinstance(v, list):
            value = [{k: val} for val in v]
            if "$and" in mongo_query.keys():
                mongo_query["$and"].extend(value)
            else:
                mongo_query["$and"] = value
    return mongo_query
 def update(_doc_cls=None, **update):
    """Transform an update spec from Django-style format to Mongo
    format.
    """
    mongo_update = {}
    for key, value in update.items():
        if key == "__raw__":
            mongo_update.update(value)
            continue
        parts = key.split("__")
        # if there is no operator, default to 'set'
        if len(parts) < 3 and parts[0] not in UPDATE_OPERATORS:
            parts.insert(0, "set")
        # Check for an operator and transform to mongo-style if there is
        op = None
        if parts[0] in UPDATE_OPERATORS:
            op = parts.pop(0)
            # Convert Pythonic names to Mongo equivalents
            operator_map = {
                "push_all": "pushAll",
                "pull_all": "pullAll",
                "dec": "inc",
                "add_to_set": "addToSet",
                "set_on_insert": "setOnInsert",
            }
            if op == "dec":
                # Support decrement by flipping a positive value's sign
                # and using 'inc'
                value = -value
            # If the operator doesn't found from operator map, the op value
            # will stay unchanged
            op = operator_map.get(op, op)
        match = None
        if parts[-1] in COMPARISON_OPERATORS:
            match = parts.pop()
        # Allow to escape operator-like field name by __
        if len(parts) > 1 and parts[-1] == "":
            parts.pop()
        if _doc_cls:
            # Switch field names to proper names [set in Field(name='foo')]
            try:
                fields = _doc_cls._lookup_field(parts)
            except Exception as e:
                raise InvalidQueryError(e)
            parts = []
            cleaned_fields = []
            appended_sub_field = False
            for field in fields:
                append_field = True
                if isinstance(field, str):
                    # Convert the S operator to $
                    if field == "S":
                        field = "$"
                    parts.append(field)
                    append_field = False
                else:
                    parts.append(field.db_field)
                if append_field:
                    appended_sub_field = False
                    cleaned_fields.append(field)
                    if hasattr(field, "field"):
                        cleaned_fields.append(field.field)
                        appended_sub_field = True
            # Convert value to proper value
            if appended_sub_field:
                field = cleaned_fields[-2]
            else:
                field = cleaned_fields[-1]
            GeoJsonBaseField = _import_class("GeoJsonBaseField")
            if isinstance(field, GeoJsonBaseField):
                value = field.to_mongo(value)
            if op == "pull":
                if field.required or value is not None:
                    if match in ("in", "nin") and not isinstance(value, dict):
                        value = _prepare_query_for_iterable(field, op, value)
                    else:
                        value = field.prepare_query_value(op, value)
            elif op == "push" and isinstance(value, (list, tuple, set)):
                value = [field.prepare_query_value(op, v) for v in value]
            elif op in (None, "set", "push"):
                if field.required or value is not None:
                    value = field.prepare_query_value(op, value)
            elif op in ("pushAll", "pullAll"):
                value = [field.prepare_query_value(op, v) for v in value]
            elif op in ("addToSet", "setOnInsert"):
                if isinstance(value, (list, tuple, set)):
                    value = [field.prepare_query_value(op, v) for v in value]
                elif field.required or value is not None:
                    value = field.prepare_query_value(op, value)
            elif op == "unset":
                value = 1
            elif op == "inc":
                value = field.prepare_query_value(op, value)
        if match:
            match = "$" + match
            value = {match: value}
        key = ".".join(parts)
        if "pull" in op and "." in key:
            # Dot operators don't work on pull operations
            # unless they point to a list field
            # Otherwise it uses nested dict syntax
            if op == "pullAll":
                raise InvalidQueryError(
                    "pullAll operations only support a single field depth"
                )
            # Look for the last list field and use dot notation until there
            field_classes = [c.__class__ for c in cleaned_fields]
            field_classes.reverse()
            ListField = _import_class("ListField")
            EmbeddedDocumentListField = _import_class("EmbeddedDocumentListField")
            if ListField in field_classes or EmbeddedDocumentListField in field_classes:
                # Join all fields via dot notation to the last ListField or EmbeddedDocumentListField
                # Then process as normal
                if ListField in field_classes:
                    _check_field = ListField
                else:
                    _check_field = EmbeddedDocumentListField
                last_listField = len(cleaned_fields) - field_classes.index(_check_field)
                key = ".".join(parts[:last_listField])
                parts = parts[last_listField:]
                parts.insert(0, key)
            parts.reverse()
            for key in parts:
                value = {key: value}
        elif op == "addToSet" and isinstance(value, list):
            value = {key: {"$each": value}}
        elif op in ("push", "pushAll"):
            if parts[-1].isdigit():
                key = ".".join(parts[0:-1])
                position = int(parts[-1])
                # $position expects an iterable. If pushing a single value,
                # wrap it in a list.
                if not isinstance(value, (set, tuple, list)):
                    value = [value]
                value = {key: {"$each": value, "$position": position}}
            else:
                if op == "pushAll":
                    op = "push"  # convert to non-deprecated keyword
                    if not isinstance(value, (set, tuple, list)):
                        value = [value]
                    value = {key: {"$each": value}}
                else:
                    value = {key: value}
        else:
            value = {key: value}
        key = "$" + op
        if key not in mongo_update:
            mongo_update[key] = value
        elif key in mongo_update and isinstance(mongo_update[key], dict):
            mongo_update[key].update(value)
    return mongo_update
 def _geo_operator(field, op, value):
    """Helper to return the query for a given geo query."""
    if op == "max_distance":
        value = {"$maxDistance": value}
    elif op == "min_distance":
        value = {"$minDistance": value}
    elif field._geo_index == pymongo.GEO2D:
        if op == "within_distance":
            value = {"$within": {"$center": value}}
        elif op == "within_spherical_distance":
            value = {"$within": {"$centerSphere": value}}
        elif op == "within_polygon":
            value = {"$within": {"$polygon": value}}
        elif op == "near":
            value = {"$near": value}
        elif op == "near_sphere":
            value = {"$nearSphere": value}
        elif op == "within_box":
            value = {"$within": {"$box": value}}
        else:
            raise NotImplementedError(
                'Geo method "%s" has not been ' "implemented for a GeoPointField" % op
            )
    else:
        if op == "geo_within":
            value = {"$geoWithin": _infer_geometry(value)}
        elif op == "geo_within_box":
            value = {"$geoWithin": {"$box": value}}
        elif op == "geo_within_polygon":
            value = {"$geoWithin": {"$polygon": value}}
        elif op == "geo_within_center":
            value = {"$geoWithin": {"$center": value}}
        elif op == "geo_within_sphere":
            value = {"$geoWithin": {"$centerSphere": value}}
        elif op == "geo_intersects":
            value = {"$geoIntersects": _infer_geometry(value)}
        elif op == "near":
            value = {"$near": _infer_geometry(value)}
        else:
            raise NotImplementedError(
                'Geo method "{}" has not been implemented for a {} '.format(
                    op, field._name
                )
            )
    return value
 def _infer_geometry(value):
    """Helper method that tries to infer the $geometry shape for a
    given value.
    """
    if isinstance(value, dict):
        if "$geometry" in value:
            return value
        elif "coordinates" in value and "type" in value:
            return {"$geometry": value}
        raise InvalidQueryError(
            "Invalid $geometry dictionary should have type and coordinates keys"
        )
    elif isinstance(value, (list, set)):
        # TODO: shouldn't we test value[0][0][0][0] to see if it is MultiPolygon?
        try:
            value[0][0][0]
            return {"$geometry": {"type": "Polygon", "coordinates": value}}
        except (TypeError, IndexError):
            pass
        try:
            value[0][0]
            return {"$geometry": {"type": "LineString", "coordinates": value}}
        except (TypeError, IndexError):
            pass
        try:
            value[0]
            return {"$geometry": {"type": "Point", "coordinates": value}}
        except (TypeError, IndexError):
            pass
    raise InvalidQueryError(
        "Invalid $geometry data. Can be either a "
        "dictionary or (nested) lists of coordinate(s)"
    )
 def _prepare_query_for_iterable(field, op, value):
    # We need a special check for BaseDocument, because - although it's iterable - using
    # it as such in the context of this method is most definitely a mistake.
    BaseDocument = _import_class("BaseDocument")
    if isinstance(value, BaseDocument):
        raise TypeError(
            "When using the `in`, `nin`, `all`, or "
            "`near`-operators you can't use a "
            "`Document`, you must wrap your object "
            "in a list (object -> [object])."
        )
    if not hasattr(value, "__iter__"):
        raise TypeError(
            "The `in`, `nin`, `all`, or "
            "`near`-operators must be applied to an "
            "iterable (e.g. a list)."
        )
    return [field.prepare_query_value(op, v) for v in value]
--- a/mongoengine/queryset/visitor.py
+++ b/mongoengine/queryset/visitor.py
@ -1,189 +0,0 @@
 import copy
 import warnings
 from mongoengine.errors import InvalidQueryError
 from mongoengine.queryset import transform
 __all__ = ("Q", "QNode")
 def warn_empty_is_deprecated():
    msg = "'empty' property is deprecated in favour of using 'not bool(filter)'"
    warnings.warn(msg, DeprecationWarning, stacklevel=2)
 class QNodeVisitor:
    """Base visitor class for visiting Q-object nodes in a query tree."""
    def visit_combination(self, combination):
        """Called by QCombination objects."""
        return combination
    def visit_query(self, query):
        """Called by (New)Q objects."""
        return query
 class DuplicateQueryConditionsError(InvalidQueryError):
    pass
 class SimplificationVisitor(QNodeVisitor):
    """Simplifies query trees by combining unnecessary 'and' connection nodes
    into a single Q-object.
    """
    def visit_combination(self, combination):
        if combination.operation == combination.AND:
            # The simplification only applies to 'simple' queries
            if all(isinstance(node, Q) for node in combination.children):
                queries = [n.query for n in combination.children]
                try:
                    return Q(**self._query_conjunction(queries))
                except DuplicateQueryConditionsError:
                    # Cannot be simplified
                    pass
        return combination
    def _query_conjunction(self, queries):
        """Merges query dicts - effectively &ing them together."""
        query_ops = set()
        combined_query = {}
        for query in queries:
            ops = set(query.keys())
            # Make sure that the same operation isn't applied more than once
            # to a single field
            intersection = ops.intersection(query_ops)
            if intersection:
                raise DuplicateQueryConditionsError()
            query_ops.update(ops)
            combined_query.update(copy.deepcopy(query))
        return combined_query
 class QueryCompilerVisitor(QNodeVisitor):
    """Compiles the nodes in a query tree to a PyMongo-compatible query
    dictionary.
    """
    def __init__(self, document):
        self.document = document
    def visit_combination(self, combination):
        operator = "$and"
        if combination.operation == combination.OR:
            operator = "$or"
        return {operator: combination.children}
    def visit_query(self, query):
        return transform.query(self.document, **query.query)
 class QNode:
    """Base class for nodes in query trees."""
    AND = 0
    OR = 1
    def to_query(self, document):
        query = self.accept(SimplificationVisitor())
        query = query.accept(QueryCompilerVisitor(document))
        return query
    def accept(self, visitor):
        raise NotImplementedError
    def _combine(self, other, operation):
        """Combine this node with another node into a QCombination
        object.
        """
        # If the other Q() is empty, ignore it and just use `self`.
        if not bool(other):
            return self
        # Or if this Q is empty, ignore it and just use `other`.
        if not bool(self):
            return other
        return QCombination(operation, [self, other])
    @property
    def empty(self):
        warn_empty_is_deprecated()
        return False
    def __or__(self, other):
        return self._combine(other, self.OR)
    def __and__(self, other):
        return self._combine(other, self.AND)
 class QCombination(QNode):
    """Represents the combination of several conditions by a given
    logical operator.
    """
    def __init__(self, operation, children):
        self.operation = operation
        self.children = []
        for node in children:
            # If the child is a combination of the same type, we can merge its
            # children directly into this combinations children
            if isinstance(node, QCombination) and node.operation == operation:
                self.children += node.children
            else:
                self.children.append(node)
    def __repr__(self):
        op = " & " if self.operation is self.AND else " | "
        return "(%s)" % op.join([repr(node) for node in self.children])
    def __bool__(self):
        return bool(self.children)
    def accept(self, visitor):
        for i in range(len(self.children)):
            if isinstance(self.children[i], QNode):
                self.children[i] = self.children[i].accept(visitor)
        return visitor.visit_combination(self)
    @property
    def empty(self):
        warn_empty_is_deprecated()
        return not bool(self.children)
    def __eq__(self, other):
        return (
            self.__class__ == other.__class__
            and self.operation == other.operation
            and self.children == other.children
        )
 class Q(QNode):
    """A simple query object, used in a query tree to build up more complex
    query structures.
    """
    def __init__(self, **query):
        self.query = query
    def __repr__(self):
        return "Q(**%s)" % repr(self.query)
    def __bool__(self):
        return bool(self.query)
    def __eq__(self, other):
        return self.__class__ == other.__class__ and self.query == other.query
    def accept(self, visitor):
        return visitor.visit_query(self)
    @property
    def empty(self):
        warn_empty_is_deprecated()
        return not bool(self.query)
--- a/mongoengine/signals.py
+++ b/mongoengine/signals.py
@ -1,25 +1,18 @@
-__all__ = (
+# -*- coding: utf-8 -*-
-    "pre_init",
+
-    "post_init",
+__all__ = ['pre_init', 'post_init', 'pre_save', 'post_save',
-    "pre_save",
+           'pre_delete', 'post_delete']
    "pre_save_post_validation",
    "post_save",
    "pre_delete",
    "post_delete",
 )
 signals_available = False
 try:
    from blinker import Namespace
    signals_available = True
 except ImportError:
-
+    class Namespace(object):
    class Namespace:
        def signal(self, name, doc=None):
            return _FakeSignal(name, doc)
-    class _FakeSignal:
+    class _FakeSignal(object):
        """If blinker is unavailable, create a fake class with the same
        interface that allows sending of signals but will fail with an
        error on anything else.  Instead of doing anything on send, it
@ -31,29 +24,23 @@ except ImportError:
            self.__doc__ = doc
        def _fail(self, *args, **kwargs):
-            raise RuntimeError(
+            raise RuntimeError('signalling support is unavailable '
-                "signalling support is unavailable "
+                               'because the blinker library is '
-                "because the blinker library is "
+                               'not installed.')
-                "not installed."
+        send = lambda *a, **kw: None
-            )
+        connect = disconnect = has_receivers_for = receivers_for = \
-
+            temporarily_connected_to = _fail
        send = lambda *a, **kw: None  # noqa
        connect = (
            disconnect
        ) = has_receivers_for = receivers_for = temporarily_connected_to = _fail
        del _fail
 # the namespace for code signals.  If you are not mongoengine code, do
 # not put signals in here.  Create your own namespace instead.
 _signals = Namespace()
-pre_init = _signals.signal("pre_init")
+pre_init = _signals.signal('pre_init')
-post_init = _signals.signal("post_init")
+post_init = _signals.signal('post_init')
-pre_save = _signals.signal("pre_save")
+pre_save = _signals.signal('pre_save')
-pre_save_post_validation = _signals.signal("pre_save_post_validation")
+post_save = _signals.signal('post_save')
-post_save = _signals.signal("post_save")
+pre_delete = _signals.signal('pre_delete')
-pre_delete = _signals.signal("pre_delete")
+post_delete = _signals.signal('post_delete')
-post_delete = _signals.signal("post_delete")
+pre_bulk_insert = _signals.signal('pre_bulk_insert')
-pre_bulk_insert = _signals.signal("pre_bulk_insert")
+post_bulk_insert = _signals.signal('post_bulk_insert')
 post_bulk_insert = _signals.signal("post_bulk_insert")
--- a/mongoengine/tests.py
+++ b/mongoengine/tests.py
@ -0,0 +1,59 @@
 from mongoengine.connection import get_db
 class query_counter(object):
    """ Query_counter contextmanager to get the number of queries. """
    def __init__(self):
        """ Construct the query_counter. """
        self.counter = 0
        self.db = get_db()
    def __enter__(self):
        """ On every with block we need to drop the profile collection. """
        self.db.set_profiling_level(0)
        self.db.system.profile.drop()
        self.db.set_profiling_level(2)
        return self
    def __exit__(self, t, value, traceback):
        """ Reset the profiling level. """
        self.db.set_profiling_level(0)
    def __eq__(self, value):
        """ == Compare querycounter. """
        return value == self._get_count()
    def __ne__(self, value):
        """ != Compare querycounter. """
        return not self.__eq__(value)
    def __lt__(self, value):
        """ < Compare querycounter. """
        return self._get_count() < value
    def __le__(self, value):
        """ <= Compare querycounter. """
        return self._get_count() <= value
    def __gt__(self, value):
        """ > Compare querycounter. """
        return self._get_count() > value
    def __ge__(self, value):
        """ >= Compare querycounter. """
        return self._get_count() >= value
    def __int__(self):
        """ int representation. """
        return self._get_count()
    def __repr__(self):
        """ repr query_counter as the number of queries. """
        return u"%s" % self._get_count()
    def _get_count(self):
        """ Get the number of queries. """
        count = self.db.system.profile.find().count() - self.counter
        self.counter += 1
        return count
--- a/python-mongoengine.spec
+++ b/python-mongoengine.spec
@ -5,7 +5,7 @@
 %define srcname mongoengine
 Name:           python-%{srcname}
-Version:        0.8.7
+Version:        0.7rc1
 Release:        1%{?dist}
 Summary:        A Python Document-Object Mapper for working with MongoDB
@ -51,4 +51,4 @@ rm -rf $RPM_BUILD_ROOT
 # %{python_sitearch}/*
 %changelog
-* See: http://docs.mongoengine.org/en/latest/changelog.html
+* See: http://readthedocs.org/docs/mongoengine-odm/en/latest/changelog.html
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@ -1,7 +0,0 @@
 black
 flake8
 pre-commit
 pytest
 ipdb
 ipython
 tox
--- a/requirements.txt
+++ b/requirements.txt
@ -0,0 +1 @@
 pymongo
--- a/setup.cfg
+++ b/setup.cfg
@ -1,18 +1,11 @@
-[flake8]
+[nosetests]
-ignore=E501,F403,F405,I201,I202,W504,W605,W503,B007
+verbosity = 3
-exclude=build,dist,docs,venv,venv3,.tox,.eggs,tests
+detailed-errors = 1
-max-complexity=47
+#with-coverage = 1
-
+#cover-erase = 1
-[tool:pytest]
+#cover-html = 1
-# Limits the discovery to tests directory
+#cover-html-dir = ../htmlcov
-# avoids that it runs for instance the benchmark
+#cover-package = mongoengine
-testpaths = tests
+py3where = build
-
+where = tests
-[isort]
+#tests =  test_bugfix.py
 known_first_party = mongoengine,tests
 default_section = THIRDPARTY
 multi_line_output = 3
 include_trailing_comma = True
 combine_as_imports = True
 line_length = 70
 ensure_newline_before_comments = 1
--- a/setup.py
+++ b/setup.py
@ -1,148 +1,80 @@
 import os
 import sys
-
+from setuptools import setup, find_packages
 from pkg_resources import normalize_path
 from setuptools import find_packages, setup
 from setuptools.command.test import test as TestCommand
 # Hack to silence atexit traceback in newer python versions
 try:
-    import multiprocessing  # noqa: F401
+    import multiprocessing
 except ImportError:
    pass
-DESCRIPTION = "MongoEngine is a Python Object-Document Mapper for working with MongoDB."
+DESCRIPTION = "A Python Document-Object Mapper for working with MongoDB"
 LONG_DESCRIPTION = None
 try:
-    with open("README.rst") as fin:
+    LONG_DESCRIPTION = open('README.rst').read()
-        LONG_DESCRIPTION = fin.read()
+except:
-except Exception:
+    pass
    LONG_DESCRIPTION = None
 def get_version(version_tuple):
-    """Return the version tuple as a string, e.g. for (0, 10, 7),
+    if not isinstance(version_tuple[-1], int):
-    return '0.10.7'.
+        return '.'.join(map(str, version_tuple[:-1])) + version_tuple[-1]
-    """
+    return '.'.join(map(str, version_tuple))
    return ".".join(map(str, version_tuple))
 class PyTest(TestCommand):
    """Will force pytest to search for tests inside the build directory
    for 2to3 converted code (used by tox), instead of the current directory.
    Required as long as we need 2to3
    Known Limitation: https://tox.readthedocs.io/en/latest/example/pytest.html#known-issues-and-limitations
    Source: https://www.hackzine.org/python-testing-with-pytest-and-2to3-plus-tox-and-travis-ci.html
    """
    # https://pytest.readthedocs.io/en/2.7.3/goodpractises.html#integration-with-setuptools-test-commands
    # Allows to provide pytest command argument through the test runner command `python setup.py test`
    # e.g: `python setup.py test -a "-k=test"`
    # This only works for 1 argument though
    user_options = [("pytest-args=", "a", "Arguments to pass to py.test")]
    def initialize_options(self):
        TestCommand.initialize_options(self)
        self.pytest_args = ""
    def finalize_options(self):
        TestCommand.finalize_options(self)
        self.test_args = ["tests"]
        self.test_suite = True
    def run_tests(self):
        # import here, cause outside the eggs aren't loaded
        import pytest
        from pkg_resources import _namespace_packages
        # Purge modules under test from sys.modules. The test loader will
        # re-import them from the build location. Required when 2to3 is used
        # with namespace packages.
        if sys.version_info >= (3,) and getattr(self.distribution, "use_2to3", False):
            module = self.test_args[-1].split(".")[0]
            if module in _namespace_packages:
                del_modules = []
                if module in sys.modules:
                    del_modules.append(module)
                module += "."
                for name in sys.modules:
                    if name.startswith(module):
                        del_modules.append(name)
                map(sys.modules.__delitem__, del_modules)
            # Run on the build directory for 2to3-built code
            # This will prevent the old 2.x code from being found
            # by py.test discovery mechanism, that apparently
            # ignores sys.path..
            ei_cmd = self.get_finalized_command("egg_info")
            self.test_args = [normalize_path(ei_cmd.egg_base)]
        cmd_args = self.test_args + ([self.pytest_args] if self.pytest_args else [])
        errno = pytest.main(cmd_args)
        sys.exit(errno)
 # Dirty hack to get version number from monogengine/__init__.py - we can't
 # import it as it depends on PyMongo and PyMongo isn't installed until this
 # file is read
-init = os.path.join(os.path.dirname(__file__), "mongoengine", "__init__.py")
+init = os.path.join(os.path.dirname(__file__), 'mongoengine', '__init__.py')
-version_line = list(filter(lambda l: l.startswith("VERSION"), open(init)))[0]
+version_line = list(filter(lambda l: l.startswith('VERSION'), open(init)))[0]
-VERSION = get_version(eval(version_line.split("=")[-1]))
+VERSION = get_version(eval(version_line.split('=')[-1]))
 print(VERSION)
 CLASSIFIERS = [
-    "Development Status :: 5 - Production/Stable",
+    'Development Status :: 4 - Beta',
-    "Intended Audience :: Developers",
+    'Intended Audience :: Developers',
-    "License :: OSI Approved :: MIT License",
+    'License :: OSI Approved :: MIT License',
-    "Operating System :: OS Independent",
+    'Operating System :: OS Independent',
-    "Programming Language :: Python",
+    'Programming Language :: Python',
    "Programming Language :: Python :: 2",
    "Programming Language :: Python :: 2.5",
    "Programming Language :: Python :: 2.6",
    "Programming Language :: Python :: 2.7",
    "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.6",
+    "Programming Language :: Python :: 3.1",
-    "Programming Language :: Python :: 3.7",
+    "Programming Language :: Python :: 3.2",
    "Programming Language :: Python :: 3.8",
    "Programming Language :: Python :: 3.9",
    "Programming Language :: Python :: 3.10",
    "Programming Language :: Python :: Implementation :: CPython",
-    "Programming Language :: Python :: Implementation :: PyPy",
+    'Topic :: Database',
-    "Topic :: Database",
+    'Topic :: Software Development :: Libraries :: Python Modules',
    "Topic :: Software Development :: Libraries :: Python Modules",
 ]
-extra_opts = {
+extra_opts = {}
-    "packages": find_packages(exclude=["tests", "tests.*"]),
+if sys.version_info[0] == 3:
-    "tests_require": [
+    extra_opts['use_2to3'] = True
-        "pytest",
+    extra_opts['tests_require'] = ['nose', 'coverage', 'blinker']
-        "pytest-cov",
+    extra_opts['packages'] = find_packages(exclude=('tests',))
-        "coverage",
+    if "test" in sys.argv or "nosetests" in sys.argv:
-        "blinker",
+        extra_opts['packages'].append("tests")
-        "Pillow>=7.0.0",
+        extra_opts['package_data'] = {"tests": ["mongoengine.png"]}
-    ],
+else:
-}
+    extra_opts['tests_require'] = ['nose', 'coverage', 'blinker', 'django>=1.3', 'PIL']
    extra_opts['packages'] = find_packages(exclude=('tests',))
-if "test" in sys.argv:
+setup(name='mongoengine',
-    extra_opts["packages"] = find_packages()
+      version=VERSION,
-    extra_opts["package_data"] = {
+      author='Harry Marr',
-        "tests": ["fields/mongoengine.png", "fields/mongodb_leaf.png"]
+      author_email='harry.marr@{nospam}gmail.com',
-    }
+      maintainer="Ross Lawley",
-
+      maintainer_email="ross.lawley@{nospam}gmail.com",
-setup(
+      url='http://mongoengine.org/',
-    name="mongoengine",
+      license='MIT',
-    version=VERSION,
+      include_package_data=True,
-    author="Harry Marr",
+      description=DESCRIPTION,
-    author_email="harry.marr@gmail.com",
+      long_description=LONG_DESCRIPTION,
-    maintainer="Stefan Wojcik",
+      platforms=['any'],
-    maintainer_email="wojcikstefan@gmail.com",
+      classifiers=CLASSIFIERS,
-    url="http://mongoengine.org/",
+      install_requires=['pymongo'],
-    download_url="https://github.com/MongoEngine/mongoengine/tarball/master",
+      test_suite='nose.collector',
-    license="MIT",
+      **extra_opts
    include_package_data=True,
    description=DESCRIPTION,
    long_description=LONG_DESCRIPTION,
    platforms=["any"],
    classifiers=CLASSIFIERS,
    python_requires=">=3.6",
    install_requires=["pymongo>=3.4, <4.0"],
    cmdclass={"test": PyTest},
    **extra_opts
 )
--- a/tests/all_warnings/test_warnings.py
+++ b/tests/all_warnings/test_warnings.py
@ -1,35 +0,0 @@
 """
 This test has been put into a module.  This is because it tests warnings that
 only get triggered on first hit.  This way we can ensure its imported into the
 top level and called first by the test suite.
 """
 import unittest
 import warnings
 from mongoengine import *
 class TestAllWarnings(unittest.TestCase):
    def setUp(self):
        connect(db="mongoenginetest")
        self.warning_list = []
        self.showwarning_default = warnings.showwarning
        warnings.showwarning = self.append_to_warning_list
    def append_to_warning_list(self, message, category, *args):
        self.warning_list.append({"message": message, "category": category})
    def tearDown(self):
        # restore default handling of warnings
        warnings.showwarning = self.showwarning_default
    def test_document_collection_syntax_warning(self):
        class NonAbstractBase(Document):
            meta = {"allow_inheritance": True}
        class InheritedDocumentFailTest(NonAbstractBase):
            meta = {"collection": "fail"}
        warning = self.warning_list[0]
        assert SyntaxWarning == warning["category"]
        assert "non_abstract_base" == InheritedDocumentFailTest._get_collection_name()
--- a/tests/document/init.py
+++ b/tests/document/init.py
--- a/tests/document/test_class_methods.py
+++ b/tests/document/test_class_methods.py
@ -1,349 +0,0 @@
 import unittest
 from mongoengine import *
 from mongoengine.connection import get_db
 from mongoengine.pymongo_support import list_collection_names
 from mongoengine.queryset import NULLIFY, PULL
 class TestClassMethods(unittest.TestCase):
    def setUp(self):
        connect(db="mongoenginetest")
        self.db = get_db()
        class Person(Document):
            name = StringField()
            age = IntField()
            non_field = True
            meta = {"allow_inheritance": True}
        self.Person = Person
    def tearDown(self):
        for collection in list_collection_names(self.db):
            self.db.drop_collection(collection)
    def test_definition(self):
        """Ensure that document may be defined using fields."""
        assert ["_cls", "age", "id", "name"] == sorted(self.Person._fields.keys())
        assert ["IntField", "ObjectIdField", "StringField", "StringField"] == sorted(
            x.__class__.__name__ for x in self.Person._fields.values()
        )
    def test_get_db(self):
        """Ensure that get_db returns the expected db."""
        db = self.Person._get_db()
        assert self.db == db
    def test_get_collection_name(self):
        """Ensure that get_collection_name returns the expected collection
        name.
        """
        collection_name = "person"
        assert collection_name == self.Person._get_collection_name()
    def test_get_collection(self):
        """Ensure that get_collection returns the expected collection."""
        collection_name = "person"
        collection = self.Person._get_collection()
        assert self.db[collection_name] == collection
    def test_drop_collection(self):
        """Ensure that the collection may be dropped from the database."""
        collection_name = "person"
        self.Person(name="Test").save()
        assert collection_name in list_collection_names(self.db)
        self.Person.drop_collection()
        assert collection_name not in list_collection_names(self.db)
    def test_register_delete_rule(self):
        """Ensure that register delete rule adds a delete rule to the document
        meta.
        """
        class Job(Document):
            employee = ReferenceField(self.Person)
        assert self.Person._meta.get("delete_rules") is None
        self.Person.register_delete_rule(Job, "employee", NULLIFY)
        assert self.Person._meta["delete_rules"] == {(Job, "employee"): NULLIFY}
    def test_compare_indexes(self):
        """Ensure that the indexes are properly created and that
        compare_indexes identifies the missing/extra indexes
        """
        class BlogPost(Document):
            author = StringField()
            title = StringField()
            description = StringField()
            tags = StringField()
            meta = {"indexes": [("author", "title")]}
        BlogPost.drop_collection()
        BlogPost.ensure_indexes()
        assert BlogPost.compare_indexes() == {"missing": [], "extra": []}
        BlogPost.ensure_index(["author", "description"])
        assert BlogPost.compare_indexes() == {
            "missing": [],
            "extra": [[("author", 1), ("description", 1)]],
        }
        BlogPost._get_collection().drop_index("author_1_description_1")
        assert BlogPost.compare_indexes() == {"missing": [], "extra": []}
        BlogPost._get_collection().drop_index("author_1_title_1")
        assert BlogPost.compare_indexes() == {
            "missing": [[("author", 1), ("title", 1)]],
            "extra": [],
        }
    def test_compare_indexes_inheritance(self):
        """Ensure that the indexes are properly created and that
        compare_indexes identifies the missing/extra indexes for subclassed
        documents (_cls included)
        """
        class BlogPost(Document):
            author = StringField()
            title = StringField()
            description = StringField()
            meta = {"allow_inheritance": True}
        class BlogPostWithTags(BlogPost):
            tags = StringField()
            tag_list = ListField(StringField())
            meta = {"indexes": [("author", "tags")]}
        BlogPost.drop_collection()
        BlogPost.ensure_indexes()
        BlogPostWithTags.ensure_indexes()
        assert BlogPost.compare_indexes() == {"missing": [], "extra": []}
        BlogPostWithTags.ensure_index(["author", "tag_list"])
        assert BlogPost.compare_indexes() == {
            "missing": [],
            "extra": [[("_cls", 1), ("author", 1), ("tag_list", 1)]],
        }
        BlogPostWithTags._get_collection().drop_index("_cls_1_author_1_tag_list_1")
        assert BlogPost.compare_indexes() == {"missing": [], "extra": []}
        BlogPostWithTags._get_collection().drop_index("_cls_1_author_1_tags_1")
        assert BlogPost.compare_indexes() == {
            "missing": [[("_cls", 1), ("author", 1), ("tags", 1)]],
            "extra": [],
        }
    def test_compare_indexes_multiple_subclasses(self):
        """Ensure that compare_indexes behaves correctly if called from a
        class, which base class has multiple subclasses
        """
        class BlogPost(Document):
            author = StringField()
            title = StringField()
            description = StringField()
            meta = {"allow_inheritance": True}
        class BlogPostWithTags(BlogPost):
            tags = StringField()
            tag_list = ListField(StringField())
            meta = {"indexes": [("author", "tags")]}
        class BlogPostWithCustomField(BlogPost):
            custom = DictField()
            meta = {"indexes": [("author", "custom")]}
        BlogPost.ensure_indexes()
        BlogPostWithTags.ensure_indexes()
        BlogPostWithCustomField.ensure_indexes()
        assert BlogPost.compare_indexes() == {"missing": [], "extra": []}
        assert BlogPostWithTags.compare_indexes() == {"missing": [], "extra": []}
        assert BlogPostWithCustomField.compare_indexes() == {"missing": [], "extra": []}
    def test_compare_indexes_for_text_indexes(self):
        """Ensure that compare_indexes behaves correctly for text indexes"""
        class Doc(Document):
            a = StringField()
            b = StringField()
            meta = {
                "indexes": [
                    {
                        "fields": ["$a", "$b"],
                        "default_language": "english",
                        "weights": {"a": 10, "b": 2},
                    }
                ]
            }
        Doc.drop_collection()
        Doc.ensure_indexes()
        actual = Doc.compare_indexes()
        expected = {"missing": [], "extra": []}
        assert actual == expected
    def test_list_indexes_inheritance(self):
        """ensure that all of the indexes are listed regardless of the super-
        or sub-class that we call it from
        """
        class BlogPost(Document):
            author = StringField()
            title = StringField()
            description = StringField()
            meta = {"allow_inheritance": True}
        class BlogPostWithTags(BlogPost):
            tags = StringField()
            meta = {"indexes": [("author", "tags")]}
        class BlogPostWithTagsAndExtraText(BlogPostWithTags):
            extra_text = StringField()
            meta = {"indexes": [("author", "tags", "extra_text")]}
        BlogPost.drop_collection()
        BlogPost.ensure_indexes()
        BlogPostWithTags.ensure_indexes()
        BlogPostWithTagsAndExtraText.ensure_indexes()
        assert BlogPost.list_indexes() == BlogPostWithTags.list_indexes()
        assert BlogPost.list_indexes() == BlogPostWithTagsAndExtraText.list_indexes()
        assert BlogPost.list_indexes() == [
            [("_cls", 1), ("author", 1), ("tags", 1)],
            [("_cls", 1), ("author", 1), ("tags", 1), ("extra_text", 1)],
            [("_id", 1)],
            [("_cls", 1)],
        ]
    def test_register_delete_rule_inherited(self):
        class Vaccine(Document):
            name = StringField(required=True)
            meta = {"indexes": ["name"]}
        class Animal(Document):
            family = StringField(required=True)
            vaccine_made = ListField(
                ReferenceField("Vaccine", reverse_delete_rule=PULL)
            )
            meta = {"allow_inheritance": True, "indexes": ["family"]}
        class Cat(Animal):
            name = StringField(required=True)
        assert Vaccine._meta["delete_rules"][(Animal, "vaccine_made")] == PULL
        assert Vaccine._meta["delete_rules"][(Cat, "vaccine_made")] == PULL
    def test_collection_naming(self):
        """Ensure that a collection with a specified name may be used."""
        class DefaultNamingTest(Document):
            pass
        assert "default_naming_test" == DefaultNamingTest._get_collection_name()
        class CustomNamingTest(Document):
            meta = {"collection": "pimp_my_collection"}
        assert "pimp_my_collection" == CustomNamingTest._get_collection_name()
        class DynamicNamingTest(Document):
            meta = {"collection": lambda c: "DYNAMO"}
        assert "DYNAMO" == DynamicNamingTest._get_collection_name()
        # Use Abstract class to handle backwards compatibility
        class BaseDocument(Document):
            meta = {"abstract": True, "collection": lambda c: c.__name__.lower()}
        class OldNamingConvention(BaseDocument):
            pass
        assert "oldnamingconvention" == OldNamingConvention._get_collection_name()
        class InheritedAbstractNamingTest(BaseDocument):
            meta = {"collection": "wibble"}
        assert "wibble" == InheritedAbstractNamingTest._get_collection_name()
        # Mixin tests
        class BaseMixin:
            meta = {"collection": lambda c: c.__name__.lower()}
        class OldMixinNamingConvention(Document, BaseMixin):
            pass
        assert (
            "oldmixinnamingconvention"
            == OldMixinNamingConvention._get_collection_name()
        )
        class BaseMixin:
            meta = {"collection": lambda c: c.__name__.lower()}
        class BaseDocument(Document, BaseMixin):
            meta = {"allow_inheritance": True}
        class MyDocument(BaseDocument):
            pass
        assert "basedocument" == MyDocument._get_collection_name()
    def test_custom_collection_name_operations(self):
        """Ensure that a collection with a specified name is used as expected."""
        collection_name = "personCollTest"
        class Person(Document):
            name = StringField()
            meta = {"collection": collection_name}
        Person(name="Test User").save()
        assert collection_name in list_collection_names(self.db)
        user_obj = self.db[collection_name].find_one()
        assert user_obj["name"] == "Test User"
        user_obj = Person.objects[0]
        assert user_obj.name == "Test User"
        Person.drop_collection()
        assert collection_name not in list_collection_names(self.db)
    def test_collection_name_and_primary(self):
        """Ensure that a collection with a specified name may be used."""
        class Person(Document):
            name = StringField(primary_key=True)
            meta = {"collection": "app"}
        Person(name="Test User").save()
        user_obj = Person.objects.first()
        assert user_obj.name == "Test User"
        Person.drop_collection()
 if __name__ == "__main__":
    unittest.main()
--- a/tests/document/test_delta.py
+++ b/tests/document/test_delta.py
@ -1,957 +0,0 @@
 import unittest
 from bson import SON
 from mongoengine import *
 from mongoengine.pymongo_support import list_collection_names
 from tests.utils import MongoDBTestCase
 class TestDelta(MongoDBTestCase):
    def setUp(self):
        super().setUp()
        class Person(Document):
            name = StringField()
            age = IntField()
            non_field = True
            meta = {"allow_inheritance": True}
        self.Person = Person
    def tearDown(self):
        for collection in list_collection_names(self.db):
            self.db.drop_collection(collection)
    def test_delta(self):
        self.delta(Document)
        self.delta(DynamicDocument)
    @staticmethod
    def delta(DocClass):
        class Doc(DocClass):
            string_field = StringField()
            int_field = IntField()
            dict_field = DictField()
            list_field = ListField()
        Doc.drop_collection()
        doc = Doc()
        doc.save()
        doc = Doc.objects.first()
        assert doc._get_changed_fields() == []
        assert doc._delta() == ({}, {})
        doc.string_field = "hello"
        assert doc._get_changed_fields() == ["string_field"]
        assert doc._delta() == ({"string_field": "hello"}, {})
        doc._changed_fields = []
        doc.int_field = 1
        assert doc._get_changed_fields() == ["int_field"]
        assert doc._delta() == ({"int_field": 1}, {})
        doc._changed_fields = []
        dict_value = {"hello": "world", "ping": "pong"}
        doc.dict_field = dict_value
        assert doc._get_changed_fields() == ["dict_field"]
        assert doc._delta() == ({"dict_field": dict_value}, {})
        doc._changed_fields = []
        list_value = ["1", 2, {"hello": "world"}]
        doc.list_field = list_value
        assert doc._get_changed_fields() == ["list_field"]
        assert doc._delta() == ({"list_field": list_value}, {})
        # Test unsetting
        doc._changed_fields = []
        doc.dict_field = {}
        assert doc._get_changed_fields() == ["dict_field"]
        assert doc._delta() == ({}, {"dict_field": 1})
        doc._changed_fields = []
        doc.list_field = []
        assert doc._get_changed_fields() == ["list_field"]
        assert doc._delta() == ({}, {"list_field": 1})
    def test_delta_recursive(self):
        self.delta_recursive(Document, EmbeddedDocument)
        self.delta_recursive(DynamicDocument, EmbeddedDocument)
        self.delta_recursive(Document, DynamicEmbeddedDocument)
        self.delta_recursive(DynamicDocument, DynamicEmbeddedDocument)
    def delta_recursive(self, DocClass, EmbeddedClass):
        class Embedded(EmbeddedClass):
            id = StringField()
            string_field = StringField()
            int_field = IntField()
            dict_field = DictField()
            list_field = ListField()
        class Doc(DocClass):
            string_field = StringField()
            int_field = IntField()
            dict_field = DictField()
            list_field = ListField()
            embedded_field = EmbeddedDocumentField(Embedded)
        Doc.drop_collection()
        doc = Doc()
        doc.save()
        doc = Doc.objects.first()
        assert doc._get_changed_fields() == []
        assert doc._delta() == ({}, {})
        embedded_1 = Embedded()
        embedded_1.id = "010101"
        embedded_1.string_field = "hello"
        embedded_1.int_field = 1
        embedded_1.dict_field = {"hello": "world"}
        embedded_1.list_field = ["1", 2, {"hello": "world"}]
        doc.embedded_field = embedded_1
        assert doc._get_changed_fields() == ["embedded_field"]
        embedded_delta = {
            "id": "010101",
            "string_field": "hello",
            "int_field": 1,
            "dict_field": {"hello": "world"},
            "list_field": ["1", 2, {"hello": "world"}],
        }
        assert doc.embedded_field._delta() == (embedded_delta, {})
        assert doc._delta() == ({"embedded_field": embedded_delta}, {})
        doc.save()
        doc = doc.reload(10)
        doc.embedded_field.dict_field = {}
        assert doc._get_changed_fields() == ["embedded_field.dict_field"]
        assert doc.embedded_field._delta() == ({}, {"dict_field": 1})
        assert doc._delta() == ({}, {"embedded_field.dict_field": 1})
        doc.save()
        doc = doc.reload(10)
        assert doc.embedded_field.dict_field == {}
        doc.embedded_field.list_field = []
        assert doc._get_changed_fields() == ["embedded_field.list_field"]
        assert doc.embedded_field._delta() == ({}, {"list_field": 1})
        assert doc._delta() == ({}, {"embedded_field.list_field": 1})
        doc.save()
        doc = doc.reload(10)
        assert doc.embedded_field.list_field == []
        embedded_2 = Embedded()
        embedded_2.string_field = "hello"
        embedded_2.int_field = 1
        embedded_2.dict_field = {"hello": "world"}
        embedded_2.list_field = ["1", 2, {"hello": "world"}]
        doc.embedded_field.list_field = ["1", 2, embedded_2]
        assert doc._get_changed_fields() == ["embedded_field.list_field"]
        assert doc.embedded_field._delta() == (
            {
                "list_field": [
                    "1",
                    2,
                    {
                        "_cls": "Embedded",
                        "string_field": "hello",
                        "dict_field": {"hello": "world"},
                        "int_field": 1,
                        "list_field": ["1", 2, {"hello": "world"}],
                    },
                ]
            },
            {},
        )
        assert doc._delta() == (
            {
                "embedded_field.list_field": [
                    "1",
                    2,
                    {
                        "_cls": "Embedded",
                        "string_field": "hello",
                        "dict_field": {"hello": "world"},
                        "int_field": 1,
                        "list_field": ["1", 2, {"hello": "world"}],
                    },
                ]
            },
            {},
        )
        doc.save()
        doc = doc.reload(10)
        assert doc.embedded_field.list_field[0] == "1"
        assert doc.embedded_field.list_field[1] == 2
        for k in doc.embedded_field.list_field[2]._fields:
            assert doc.embedded_field.list_field[2][k] == embedded_2[k]
        doc.embedded_field.list_field[2].string_field = "world"
        assert doc._get_changed_fields() == ["embedded_field.list_field.2.string_field"]
        assert doc.embedded_field._delta() == (
            {"list_field.2.string_field": "world"},
            {},
        )
        assert doc._delta() == (
            {"embedded_field.list_field.2.string_field": "world"},
            {},
        )
        doc.save()
        doc = doc.reload(10)
        assert doc.embedded_field.list_field[2].string_field == "world"
        # Test multiple assignments
        doc.embedded_field.list_field[2].string_field = "hello world"
        doc.embedded_field.list_field[2] = doc.embedded_field.list_field[2]
        assert doc._get_changed_fields() == ["embedded_field.list_field.2"]
        assert doc.embedded_field._delta() == (
            {
                "list_field.2": {
                    "_cls": "Embedded",
                    "string_field": "hello world",
                    "int_field": 1,
                    "list_field": ["1", 2, {"hello": "world"}],
                    "dict_field": {"hello": "world"},
                }
            },
            {},
        )
        assert doc._delta() == (
            {
                "embedded_field.list_field.2": {
                    "_cls": "Embedded",
                    "string_field": "hello world",
                    "int_field": 1,
                    "list_field": ["1", 2, {"hello": "world"}],
                    "dict_field": {"hello": "world"},
                }
            },
            {},
        )
        doc.save()
        doc = doc.reload(10)
        assert doc.embedded_field.list_field[2].string_field == "hello world"
        # Test list native methods
        doc.embedded_field.list_field[2].list_field.pop(0)
        assert doc._delta() == (
            {"embedded_field.list_field.2.list_field": [2, {"hello": "world"}]},
            {},
        )
        doc.save()
        doc = doc.reload(10)
        doc.embedded_field.list_field[2].list_field.append(1)
        assert doc._delta() == (
            {"embedded_field.list_field.2.list_field": [2, {"hello": "world"}, 1]},
            {},
        )
        doc.save()
        doc = doc.reload(10)
        assert doc.embedded_field.list_field[2].list_field == [2, {"hello": "world"}, 1]
        doc.embedded_field.list_field[2].list_field.sort(key=str)
        doc.save()
        doc = doc.reload(10)
        assert doc.embedded_field.list_field[2].list_field == [1, 2, {"hello": "world"}]
        del doc.embedded_field.list_field[2].list_field[2]["hello"]
        assert doc._delta() == (
            {},
            {"embedded_field.list_field.2.list_field.2.hello": 1},
        )
        doc.save()
        doc = doc.reload(10)
        del doc.embedded_field.list_field[2].list_field
        assert doc._delta() == ({}, {"embedded_field.list_field.2.list_field": 1})
        doc.save()
        doc = doc.reload(10)
        doc.dict_field["Embedded"] = embedded_1
        doc.save()
        doc = doc.reload(10)
        doc.dict_field["Embedded"].string_field = "Hello World"
        assert doc._get_changed_fields() == ["dict_field.Embedded.string_field"]
        assert doc._delta() == ({"dict_field.Embedded.string_field": "Hello World"}, {})
    def test_circular_reference_deltas(self):
        self.circular_reference_deltas(Document, Document)
        self.circular_reference_deltas(Document, DynamicDocument)
        self.circular_reference_deltas(DynamicDocument, Document)
        self.circular_reference_deltas(DynamicDocument, DynamicDocument)
    def circular_reference_deltas(self, DocClass1, DocClass2):
        class Person(DocClass1):
            name = StringField()
            owns = ListField(ReferenceField("Organization"))
        class Organization(DocClass2):
            name = StringField()
            owner = ReferenceField("Person")
        Person.drop_collection()
        Organization.drop_collection()
        person = Person(name="owner").save()
        organization = Organization(name="company").save()
        person.owns.append(organization)
        organization.owner = person
        person.save()
        organization.save()
        p = Person.objects[0].select_related()
        o = Organization.objects.first()
        assert p.owns[0] == o
        assert o.owner == p
    def test_circular_reference_deltas_2(self):
        self.circular_reference_deltas_2(Document, Document)
        self.circular_reference_deltas_2(Document, DynamicDocument)
        self.circular_reference_deltas_2(DynamicDocument, Document)
        self.circular_reference_deltas_2(DynamicDocument, DynamicDocument)
    def circular_reference_deltas_2(self, DocClass1, DocClass2, dbref=True):
        class Person(DocClass1):
            name = StringField()
            owns = ListField(ReferenceField("Organization", dbref=dbref))
            employer = ReferenceField("Organization", dbref=dbref)
        class Organization(DocClass2):
            name = StringField()
            owner = ReferenceField("Person", dbref=dbref)
            employees = ListField(ReferenceField("Person", dbref=dbref))
        Person.drop_collection()
        Organization.drop_collection()
        person = Person(name="owner").save()
        employee = Person(name="employee").save()
        organization = Organization(name="company").save()
        person.owns.append(organization)
        organization.owner = person
        organization.employees.append(employee)
        employee.employer = organization
        person.save()
        organization.save()
        employee.save()
        p = Person.objects.get(name="owner")
        e = Person.objects.get(name="employee")
        o = Organization.objects.first()
        assert p.owns[0] == o
        assert o.owner == p
        assert e.employer == o
        return person, organization, employee
    def test_delta_db_field(self):
        self.delta_db_field(Document)
        self.delta_db_field(DynamicDocument)
    def delta_db_field(self, DocClass):
        class Doc(DocClass):
            string_field = StringField(db_field="db_string_field")
            int_field = IntField(db_field="db_int_field")
            dict_field = DictField(db_field="db_dict_field")
            list_field = ListField(db_field="db_list_field")
        Doc.drop_collection()
        doc = Doc()
        doc.save()
        doc = Doc.objects.first()
        assert doc._get_changed_fields() == []
        assert doc._delta() == ({}, {})
        doc.string_field = "hello"
        assert doc._get_changed_fields() == ["db_string_field"]
        assert doc._delta() == ({"db_string_field": "hello"}, {})
        doc._changed_fields = []
        doc.int_field = 1
        assert doc._get_changed_fields() == ["db_int_field"]
        assert doc._delta() == ({"db_int_field": 1}, {})
        doc._changed_fields = []
        dict_value = {"hello": "world", "ping": "pong"}
        doc.dict_field = dict_value
        assert doc._get_changed_fields() == ["db_dict_field"]
        assert doc._delta() == ({"db_dict_field": dict_value}, {})
        doc._changed_fields = []
        list_value = ["1", 2, {"hello": "world"}]
        doc.list_field = list_value
        assert doc._get_changed_fields() == ["db_list_field"]
        assert doc._delta() == ({"db_list_field": list_value}, {})
        # Test unsetting
        doc._changed_fields = []
        doc.dict_field = {}
        assert doc._get_changed_fields() == ["db_dict_field"]
        assert doc._delta() == ({}, {"db_dict_field": 1})
        doc._changed_fields = []
        doc.list_field = []
        assert doc._get_changed_fields() == ["db_list_field"]
        assert doc._delta() == ({}, {"db_list_field": 1})
        # Test it saves that data
        doc = Doc()
        doc.save()
        doc.string_field = "hello"
        doc.int_field = 1
        doc.dict_field = {"hello": "world"}
        doc.list_field = ["1", 2, {"hello": "world"}]
        doc.save()
        doc = doc.reload(10)
        assert doc.string_field == "hello"
        assert doc.int_field == 1
        assert doc.dict_field == {"hello": "world"}
        assert doc.list_field == ["1", 2, {"hello": "world"}]
    def test_delta_recursive_db_field_on_doc_and_embeddeddoc(self):
        self.delta_recursive_db_field(Document, EmbeddedDocument)
    def test_delta_recursive_db_field_on_doc_and_dynamicembeddeddoc(self):
        self.delta_recursive_db_field(Document, DynamicEmbeddedDocument)
    def test_delta_recursive_db_field_on_dynamicdoc_and_embeddeddoc(self):
        self.delta_recursive_db_field(DynamicDocument, EmbeddedDocument)
    def test_delta_recursive_db_field_on_dynamicdoc_and_dynamicembeddeddoc(self):
        self.delta_recursive_db_field(DynamicDocument, DynamicEmbeddedDocument)
    @staticmethod
    def delta_recursive_db_field(DocClass, EmbeddedClass):
        class Embedded(EmbeddedClass):
            string_field = StringField(db_field="db_string_field")
            int_field = IntField(db_field="db_int_field")
            dict_field = DictField(db_field="db_dict_field")
            list_field = ListField(db_field="db_list_field")
        class Doc(DocClass):
            string_field = StringField(db_field="db_string_field")
            int_field = IntField(db_field="db_int_field")
            dict_field = DictField(db_field="db_dict_field")
            list_field = ListField(db_field="db_list_field")
            embedded_field = EmbeddedDocumentField(
                Embedded, db_field="db_embedded_field"
            )
        Doc.drop_collection()
        doc = Doc()
        doc.save()
        doc = Doc.objects.first()
        assert doc._get_changed_fields() == []
        assert doc._delta() == ({}, {})
        embedded_1 = Embedded()
        embedded_1.string_field = "hello"
        embedded_1.int_field = 1
        embedded_1.dict_field = {"hello": "world"}
        embedded_1.list_field = ["1", 2, {"hello": "world"}]
        doc.embedded_field = embedded_1
        assert doc._get_changed_fields() == ["db_embedded_field"]
        embedded_delta = {
            "db_string_field": "hello",
            "db_int_field": 1,
            "db_dict_field": {"hello": "world"},
            "db_list_field": ["1", 2, {"hello": "world"}],
        }
        assert doc.embedded_field._delta() == (embedded_delta, {})
        assert doc._delta() == ({"db_embedded_field": embedded_delta}, {})
        doc.save()
        doc = doc.reload(10)
        doc.embedded_field.dict_field = {}
        assert doc._get_changed_fields() == ["db_embedded_field.db_dict_field"]
        assert doc.embedded_field._delta() == ({}, {"db_dict_field": 1})
        assert doc._delta() == ({}, {"db_embedded_field.db_dict_field": 1})
        doc.save()
        doc = doc.reload(10)
        assert doc.embedded_field.dict_field == {}
        assert doc._get_changed_fields() == []
        doc.embedded_field.list_field = []
        assert doc._get_changed_fields() == ["db_embedded_field.db_list_field"]
        assert doc.embedded_field._delta() == ({}, {"db_list_field": 1})
        assert doc._delta() == ({}, {"db_embedded_field.db_list_field": 1})
        doc.save()
        doc = doc.reload(10)
        assert doc.embedded_field.list_field == []
        embedded_2 = Embedded()
        embedded_2.string_field = "hello"
        embedded_2.int_field = 1
        embedded_2.dict_field = {"hello": "world"}
        embedded_2.list_field = ["1", 2, {"hello": "world"}]
        doc.embedded_field.list_field = ["1", 2, embedded_2]
        assert doc._get_changed_fields() == ["db_embedded_field.db_list_field"]
        assert doc.embedded_field._delta() == (
            {
                "db_list_field": [
                    "1",
                    2,
                    {
                        "_cls": "Embedded",
                        "db_string_field": "hello",
                        "db_dict_field": {"hello": "world"},
                        "db_int_field": 1,
                        "db_list_field": ["1", 2, {"hello": "world"}],
                    },
                ]
            },
            {},
        )
        assert doc._delta() == (
            {
                "db_embedded_field.db_list_field": [
                    "1",
                    2,
                    {
                        "_cls": "Embedded",
                        "db_string_field": "hello",
                        "db_dict_field": {"hello": "world"},
                        "db_int_field": 1,
                        "db_list_field": ["1", 2, {"hello": "world"}],
                    },
                ]
            },
            {},
        )
        doc.save()
        assert doc._get_changed_fields() == []
        doc = doc.reload(10)
        assert doc.embedded_field.list_field[0] == "1"
        assert doc.embedded_field.list_field[1] == 2
        for k in doc.embedded_field.list_field[2]._fields:
            assert doc.embedded_field.list_field[2][k] == embedded_2[k]
        doc.embedded_field.list_field[2].string_field = "world"
        assert doc._get_changed_fields() == [
            "db_embedded_field.db_list_field.2.db_string_field"
        ]
        assert doc.embedded_field._delta() == (
            {"db_list_field.2.db_string_field": "world"},
            {},
        )
        assert doc._delta() == (
            {"db_embedded_field.db_list_field.2.db_string_field": "world"},
            {},
        )
        doc.save()
        doc = doc.reload(10)
        assert doc.embedded_field.list_field[2].string_field == "world"
        # Test multiple assignments
        doc.embedded_field.list_field[2].string_field = "hello world"
        doc.embedded_field.list_field[2] = doc.embedded_field.list_field[2]
        assert doc._get_changed_fields() == ["db_embedded_field.db_list_field.2"]
        assert doc.embedded_field._delta() == (
            {
                "db_list_field.2": {
                    "_cls": "Embedded",
                    "db_string_field": "hello world",
                    "db_int_field": 1,
                    "db_list_field": ["1", 2, {"hello": "world"}],
                    "db_dict_field": {"hello": "world"},
                }
            },
            {},
        )
        assert doc._delta() == (
            {
                "db_embedded_field.db_list_field.2": {
                    "_cls": "Embedded",
                    "db_string_field": "hello world",
                    "db_int_field": 1,
                    "db_list_field": ["1", 2, {"hello": "world"}],
                    "db_dict_field": {"hello": "world"},
                }
            },
            {},
        )
        doc.save()
        doc = doc.reload(10)
        assert doc.embedded_field.list_field[2].string_field == "hello world"
        # Test list native methods
        doc.embedded_field.list_field[2].list_field.pop(0)
        assert doc._delta() == (
            {
                "db_embedded_field.db_list_field.2.db_list_field": [
                    2,
                    {"hello": "world"},
                ]
            },
            {},
        )
        doc.save()
        doc = doc.reload(10)
        doc.embedded_field.list_field[2].list_field.append(1)
        assert doc._delta() == (
            {
                "db_embedded_field.db_list_field.2.db_list_field": [
                    2,
                    {"hello": "world"},
                    1,
                ]
            },
            {},
        )
        doc.save()
        doc = doc.reload(10)
        assert doc.embedded_field.list_field[2].list_field == [2, {"hello": "world"}, 1]
        doc.embedded_field.list_field[2].list_field.sort(key=str)
        doc.save()
        doc = doc.reload(10)
        assert doc.embedded_field.list_field[2].list_field == [1, 2, {"hello": "world"}]
        del doc.embedded_field.list_field[2].list_field[2]["hello"]
        assert doc._delta() == (
            {},
            {"db_embedded_field.db_list_field.2.db_list_field.2.hello": 1},
        )
        doc.save()
        doc = doc.reload(10)
        assert doc._delta() == (
            {},
            {},
        )
        del doc.embedded_field.list_field[2].list_field
        assert doc._delta() == (
            {},
            {"db_embedded_field.db_list_field.2.db_list_field": 1},
        )
    def test_delta_for_dynamic_documents(self):
        class Person(DynamicDocument):
            name = StringField()
            meta = {"allow_inheritance": True}
        Person.drop_collection()
        p = Person(name="James", age=34)
        assert p._delta() == (
            SON([("_cls", "Person"), ("name", "James"), ("age", 34)]),
            {},
        )
        p.doc = 123
        del p.doc
        assert p._delta() == (
            SON([("_cls", "Person"), ("name", "James"), ("age", 34)]),
            {},
        )
        p = Person()
        p.name = "Dean"
        p.age = 22
        p.save()
        p.age = 24
        assert p.age == 24
        assert p._get_changed_fields() == ["age"]
        assert p._delta() == ({"age": 24}, {})
        p = Person.objects(age=22).get()
        p.age = 24
        assert p.age == 24
        assert p._get_changed_fields() == ["age"]
        assert p._delta() == ({"age": 24}, {})
        p.save()
        assert 1 == Person.objects(age=24).count()
    def test_dynamic_delta(self):
        class Doc(DynamicDocument):
            pass
        Doc.drop_collection()
        doc = Doc()
        doc.save()
        doc = Doc.objects.first()
        assert doc._get_changed_fields() == []
        assert doc._delta() == ({}, {})
        doc.string_field = "hello"
        assert doc._get_changed_fields() == ["string_field"]
        assert doc._delta() == ({"string_field": "hello"}, {})
        doc._changed_fields = []
        doc.int_field = 1
        assert doc._get_changed_fields() == ["int_field"]
        assert doc._delta() == ({"int_field": 1}, {})
        doc._changed_fields = []
        dict_value = {"hello": "world", "ping": "pong"}
        doc.dict_field = dict_value
        assert doc._get_changed_fields() == ["dict_field"]
        assert doc._delta() == ({"dict_field": dict_value}, {})
        doc._changed_fields = []
        list_value = ["1", 2, {"hello": "world"}]
        doc.list_field = list_value
        assert doc._get_changed_fields() == ["list_field"]
        assert doc._delta() == ({"list_field": list_value}, {})
        # Test unsetting
        doc._changed_fields = []
        doc.dict_field = {}
        assert doc._get_changed_fields() == ["dict_field"]
        assert doc._delta() == ({}, {"dict_field": 1})
        doc._changed_fields = []
        doc.list_field = []
        assert doc._get_changed_fields() == ["list_field"]
        assert doc._delta() == ({}, {"list_field": 1})
    def test_delta_with_dbref_true(self):
        person, organization, employee = self.circular_reference_deltas_2(
            Document, Document, True
        )
        employee.name = "test"
        assert organization._get_changed_fields() == []
        updates, removals = organization._delta()
        assert removals == {}
        assert updates == {}
        organization.employees.append(person)
        updates, removals = organization._delta()
        assert removals == {}
        assert "employees" in updates
    def test_delta_with_dbref_false(self):
        person, organization, employee = self.circular_reference_deltas_2(
            Document, Document, False
        )
        employee.name = "test"
        assert organization._get_changed_fields() == []
        updates, removals = organization._delta()
        assert removals == {}
        assert updates == {}
        organization.employees.append(person)
        updates, removals = organization._delta()
        assert removals == {}
        assert "employees" in updates
    def test_nested_nested_fields_mark_as_changed(self):
        class EmbeddedDoc(EmbeddedDocument):
            name = StringField()
        class MyDoc(Document):
            subs = MapField(MapField(EmbeddedDocumentField(EmbeddedDoc)))
            name = StringField()
        MyDoc.drop_collection()
        MyDoc(name="testcase1", subs={"a": {"b": EmbeddedDoc(name="foo")}}).save()
        mydoc = MyDoc.objects.first()
        subdoc = mydoc.subs["a"]["b"]
        subdoc.name = "bar"
        assert subdoc._get_changed_fields() == ["name"]
        assert mydoc._get_changed_fields() == ["subs.a.b.name"]
        mydoc._clear_changed_fields()
        assert mydoc._get_changed_fields() == []
    def test_nested_nested_fields_db_field_set__gets_mark_as_changed_and_cleaned(self):
        class EmbeddedDoc(EmbeddedDocument):
            name = StringField(db_field="db_name")
        class MyDoc(Document):
            embed = EmbeddedDocumentField(EmbeddedDoc, db_field="db_embed")
            name = StringField(db_field="db_name")
        MyDoc.drop_collection()
        MyDoc(name="testcase1", embed=EmbeddedDoc(name="foo")).save()
        mydoc = MyDoc.objects.first()
        mydoc.embed.name = "foo1"
        assert mydoc.embed._get_changed_fields() == ["db_name"]
        assert mydoc._get_changed_fields() == ["db_embed.db_name"]
        mydoc = MyDoc.objects.first()
        embed = EmbeddedDoc(name="foo2")
        embed.name = "bar"
        mydoc.embed = embed
        assert embed._get_changed_fields() == ["db_name"]
        assert mydoc._get_changed_fields() == ["db_embed"]
        mydoc._clear_changed_fields()
        assert mydoc._get_changed_fields() == []
    def test_lower_level_mark_as_changed(self):
        class EmbeddedDoc(EmbeddedDocument):
            name = StringField()
        class MyDoc(Document):
            subs = MapField(EmbeddedDocumentField(EmbeddedDoc))
        MyDoc.drop_collection()
        MyDoc().save()
        mydoc = MyDoc.objects.first()
        mydoc.subs["a"] = EmbeddedDoc()
        assert mydoc._get_changed_fields() == ["subs.a"]
        subdoc = mydoc.subs["a"]
        subdoc.name = "bar"
        assert subdoc._get_changed_fields() == ["name"]
        assert mydoc._get_changed_fields() == ["subs.a"]
        mydoc.save()
        mydoc._clear_changed_fields()
        assert mydoc._get_changed_fields() == []
    def test_upper_level_mark_as_changed(self):
        class EmbeddedDoc(EmbeddedDocument):
            name = StringField()
        class MyDoc(Document):
            subs = MapField(EmbeddedDocumentField(EmbeddedDoc))
        MyDoc.drop_collection()
        MyDoc(subs={"a": EmbeddedDoc(name="foo")}).save()
        mydoc = MyDoc.objects.first()
        subdoc = mydoc.subs["a"]
        subdoc.name = "bar"
        assert subdoc._get_changed_fields() == ["name"]
        assert mydoc._get_changed_fields() == ["subs.a.name"]
        mydoc.subs["a"] = EmbeddedDoc()
        assert mydoc._get_changed_fields() == ["subs.a"]
        mydoc.save()
        mydoc._clear_changed_fields()
        assert mydoc._get_changed_fields() == []
    def test_referenced_object_changed_attributes(self):
        """Ensures that when you save a new reference to a field, the referenced object isn't altered"""
        class Organization(Document):
            name = StringField()
        class User(Document):
            name = StringField()
            org = ReferenceField("Organization", required=True)
        Organization.drop_collection()
        User.drop_collection()
        org1 = Organization(name="Org 1")
        org1.save()
        org2 = Organization(name="Org 2")
        org2.save()
        user = User(name="Fred", org=org1)
        user.save()
        org1.reload()
        org2.reload()
        user.reload()
        assert org1.name == "Org 1"
        assert org2.name == "Org 2"
        assert user.name == "Fred"
        user.name = "Harold"
        user.org = org2
        org2.name = "New Org 2"
        assert org2.name == "New Org 2"
        user.save()
        org2.save()
        assert org2.name == "New Org 2"
        org2.reload()
        assert org2.name == "New Org 2"
    def test_delta_for_nested_map_fields(self):
        class UInfoDocument(Document):
            phone = StringField()
        class EmbeddedRole(EmbeddedDocument):
            type = StringField()
        class EmbeddedUser(EmbeddedDocument):
            name = StringField()
            roles = MapField(field=EmbeddedDocumentField(EmbeddedRole))
            rolist = ListField(field=EmbeddedDocumentField(EmbeddedRole))
            info = ReferenceField(UInfoDocument)
        class Doc(Document):
            users = MapField(field=EmbeddedDocumentField(EmbeddedUser))
            num = IntField(default=-1)
        Doc.drop_collection()
        doc = Doc(num=1)
        doc.users["007"] = EmbeddedUser(name="Agent007")
        doc.save()
        uinfo = UInfoDocument(phone="79089269066")
        uinfo.save()
        d = Doc.objects(num=1).first()
        d.users["007"]["roles"]["666"] = EmbeddedRole(type="superadmin")
        d.users["007"]["rolist"].append(EmbeddedRole(type="oops"))
        d.users["007"]["info"] = uinfo
        delta = d._delta()
        assert True == ("users.007.roles.666" in delta[0])
        assert True == ("users.007.rolist" in delta[0])
        assert True == ("users.007.info" in delta[0])
        assert "superadmin" == delta[0]["users.007.roles.666"]["type"]
        assert "oops" == delta[0]["users.007.rolist"][0]["type"]
        assert uinfo.id == delta[0]["users.007.info"]
 if __name__ == "__main__":
    unittest.main()
--- a/tests/document/test_dynamic.py
+++ b/tests/document/test_dynamic.py
@ -1,439 +0,0 @@
 import unittest
 import pytest
 from mongoengine import *
 from tests.utils import MongoDBTestCase
 __all__ = ("TestDynamicDocument",)
 class TestDynamicDocument(MongoDBTestCase):
    def setUp(self):
        super().setUp()
        class Person(DynamicDocument):
            name = StringField()
            meta = {"allow_inheritance": True}
        Person.drop_collection()
        self.Person = Person
    def test_simple_dynamic_document(self):
        """Ensures simple dynamic documents are saved correctly"""
        p = self.Person()
        p.name = "James"
        p.age = 34
        assert p.to_mongo() == {"_cls": "Person", "name": "James", "age": 34}
        assert p.to_mongo().keys() == ["_cls", "name", "age"]
        p.save()
        assert p.to_mongo().keys() == ["_id", "_cls", "name", "age"]
        assert self.Person.objects.first().age == 34
        # Confirm no changes to self.Person
        assert not hasattr(self.Person, "age")
    def test_dynamic_document_parse_values_in_constructor_like_document_do(self):
        class ProductDynamicDocument(DynamicDocument):
            title = StringField()
            price = FloatField()
        class ProductDocument(Document):
            title = StringField()
            price = FloatField()
        product = ProductDocument(title="Blabla", price="12.5")
        dyn_product = ProductDynamicDocument(title="Blabla", price="12.5")
        assert product.price == dyn_product.price == 12.5
    def test_change_scope_of_variable(self):
        """Test changing the scope of a dynamic field has no adverse effects"""
        p = self.Person()
        p.name = "Dean"
        p.misc = 22
        p.save()
        p = self.Person.objects.get()
        p.misc = {"hello": "world"}
        p.save()
        p = self.Person.objects.get()
        assert p.misc == {"hello": "world"}
    def test_delete_dynamic_field(self):
        """Test deleting a dynamic field works"""
        self.Person.drop_collection()
        p = self.Person()
        p.name = "Dean"
        p.misc = 22
        p.save()
        p = self.Person.objects.get()
        p.misc = {"hello": "world"}
        p.save()
        p = self.Person.objects.get()
        assert p.misc == {"hello": "world"}
        collection = self.db[self.Person._get_collection_name()]
        obj = collection.find_one()
        assert sorted(obj.keys()) == ["_cls", "_id", "misc", "name"]
        del p.misc
        p.save()
        p = self.Person.objects.get()
        assert not hasattr(p, "misc")
        obj = collection.find_one()
        assert sorted(obj.keys()) == ["_cls", "_id", "name"]
    def test_reload_after_unsetting(self):
        p = self.Person()
        p.misc = 22
        p.save()
        p.update(unset__misc=1)
        p.reload()
    def test_reload_dynamic_field(self):
        self.Person.objects.delete()
        p = self.Person.objects.create()
        p.update(age=1)
        assert len(p._data) == 3
        assert sorted(p._data.keys()) == ["_cls", "id", "name"]
        p.reload()
        assert len(p._data) == 4
        assert sorted(p._data.keys()) == ["_cls", "age", "id", "name"]
    def test_fields_without_underscore(self):
        """Ensure we can query dynamic fields"""
        Person = self.Person
        p = self.Person(name="Dean")
        p.save()
        raw_p = Person.objects.as_pymongo().get(id=p.id)
        assert raw_p == {"_cls": "Person", "_id": p.id, "name": "Dean"}
        p.name = "OldDean"
        p.newattr = "garbage"
        p.save()
        raw_p = Person.objects.as_pymongo().get(id=p.id)
        assert raw_p == {
            "_cls": "Person",
            "_id": p.id,
            "name": "OldDean",
            "newattr": "garbage",
        }
    def test_fields_containing_underscore(self):
        """Ensure we can query dynamic fields"""
        class WeirdPerson(DynamicDocument):
            name = StringField()
            _name = StringField()
        WeirdPerson.drop_collection()
        p = WeirdPerson(name="Dean", _name="Dean")
        p.save()
        raw_p = WeirdPerson.objects.as_pymongo().get(id=p.id)
        assert raw_p == {"_id": p.id, "_name": "Dean", "name": "Dean"}
        p.name = "OldDean"
        p._name = "NewDean"
        p._newattr1 = "garbage"  # Unknown fields won't be added
        p.save()
        raw_p = WeirdPerson.objects.as_pymongo().get(id=p.id)
        assert raw_p == {"_id": p.id, "_name": "NewDean", "name": "OldDean"}
    def test_dynamic_document_queries(self):
        """Ensure we can query dynamic fields"""
        p = self.Person()
        p.name = "Dean"
        p.age = 22
        p.save()
        assert 1 == self.Person.objects(age=22).count()
        p = self.Person.objects(age=22)
        p = p.get()
        assert 22 == p.age
    def test_complex_dynamic_document_queries(self):
        class Person(DynamicDocument):
            name = StringField()
        Person.drop_collection()
        p = Person(name="test")
        p.age = "ten"
        p.save()
        p1 = Person(name="test1")
        p1.age = "less then ten and a half"
        p1.save()
        p2 = Person(name="test2")
        p2.age = 10
        p2.save()
        assert Person.objects(age__icontains="ten").count() == 2
        assert Person.objects(age__gte=10).count() == 1
    def test_complex_data_lookups(self):
        """Ensure you can query dynamic document dynamic fields"""
        p = self.Person()
        p.misc = {"hello": "world"}
        p.save()
        assert 1 == self.Person.objects(misc__hello="world").count()
    def test_three_level_complex_data_lookups(self):
        """Ensure you can query three level document dynamic fields"""
        self.Person.objects.create(misc={"hello": {"hello2": "world"}})
        assert 1 == self.Person.objects(misc__hello__hello2="world").count()
    def test_complex_embedded_document_validation(self):
        """Ensure embedded dynamic documents may be validated"""
        class Embedded(DynamicEmbeddedDocument):
            content = URLField()
        class Doc(DynamicDocument):
            pass
        Doc.drop_collection()
        doc = Doc()
        embedded_doc_1 = Embedded(content="http://mongoengine.org")
        embedded_doc_1.validate()
        embedded_doc_2 = Embedded(content="this is not a url")
        with pytest.raises(ValidationError):
            embedded_doc_2.validate()
        doc.embedded_field_1 = embedded_doc_1
        doc.embedded_field_2 = embedded_doc_2
        with pytest.raises(ValidationError):
            doc.validate()
    def test_inheritance(self):
        """Ensure that dynamic document plays nice with inheritance"""
        class Employee(self.Person):
            salary = IntField()
        Employee.drop_collection()
        assert "name" in Employee._fields
        assert "salary" in Employee._fields
        assert Employee._get_collection_name() == self.Person._get_collection_name()
        joe_bloggs = Employee()
        joe_bloggs.name = "Joe Bloggs"
        joe_bloggs.salary = 10
        joe_bloggs.age = 20
        joe_bloggs.save()
        assert 1 == self.Person.objects(age=20).count()
        assert 1 == Employee.objects(age=20).count()
        joe_bloggs = self.Person.objects.first()
        assert isinstance(joe_bloggs, Employee)
    def test_embedded_dynamic_document(self):
        """Test dynamic embedded documents"""
        class Embedded(DynamicEmbeddedDocument):
            pass
        class Doc(DynamicDocument):
            pass
        Doc.drop_collection()
        doc = Doc()
        embedded_1 = Embedded()
        embedded_1.string_field = "hello"
        embedded_1.int_field = 1
        embedded_1.dict_field = {"hello": "world"}
        embedded_1.list_field = ["1", 2, {"hello": "world"}]
        doc.embedded_field = embedded_1
        assert doc.to_mongo() == {
            "embedded_field": {
                "_cls": "Embedded",
                "string_field": "hello",
                "int_field": 1,
                "dict_field": {"hello": "world"},
                "list_field": ["1", 2, {"hello": "world"}],
            }
        }
        doc.save()
        doc = Doc.objects.first()
        assert doc.embedded_field.__class__ == Embedded
        assert doc.embedded_field.string_field == "hello"
        assert doc.embedded_field.int_field == 1
        assert doc.embedded_field.dict_field == {"hello": "world"}
        assert doc.embedded_field.list_field == ["1", 2, {"hello": "world"}]
    def test_complex_embedded_documents(self):
        """Test complex dynamic embedded documents setups"""
        class Embedded(DynamicEmbeddedDocument):
            pass
        class Doc(DynamicDocument):
            pass
        Doc.drop_collection()
        doc = Doc()
        embedded_1 = Embedded()
        embedded_1.string_field = "hello"
        embedded_1.int_field = 1
        embedded_1.dict_field = {"hello": "world"}
        embedded_2 = Embedded()
        embedded_2.string_field = "hello"
        embedded_2.int_field = 1
        embedded_2.dict_field = {"hello": "world"}
        embedded_2.list_field = ["1", 2, {"hello": "world"}]
        embedded_1.list_field = ["1", 2, embedded_2]
        doc.embedded_field = embedded_1
        assert doc.to_mongo() == {
            "embedded_field": {
                "_cls": "Embedded",
                "string_field": "hello",
                "int_field": 1,
                "dict_field": {"hello": "world"},
                "list_field": [
                    "1",
                    2,
                    {
                        "_cls": "Embedded",
                        "string_field": "hello",
                        "int_field": 1,
                        "dict_field": {"hello": "world"},
                        "list_field": ["1", 2, {"hello": "world"}],
                    },
                ],
            }
        }
        doc.save()
        doc = Doc.objects.first()
        assert doc.embedded_field.__class__ == Embedded
        assert doc.embedded_field.string_field == "hello"
        assert doc.embedded_field.int_field == 1
        assert doc.embedded_field.dict_field == {"hello": "world"}
        assert doc.embedded_field.list_field[0] == "1"
        assert doc.embedded_field.list_field[1] == 2
        embedded_field = doc.embedded_field.list_field[2]
        assert embedded_field.__class__ == Embedded
        assert embedded_field.string_field == "hello"
        assert embedded_field.int_field == 1
        assert embedded_field.dict_field == {"hello": "world"}
        assert embedded_field.list_field == ["1", 2, {"hello": "world"}]
    def test_dynamic_and_embedded(self):
        """Ensure embedded documents play nicely"""
        class Address(EmbeddedDocument):
            city = StringField()
        class Person(DynamicDocument):
            name = StringField()
        Person.drop_collection()
        Person(name="Ross", address=Address(city="London")).save()
        person = Person.objects.first()
        person.address.city = "Lundenne"
        person.save()
        assert Person.objects.first().address.city == "Lundenne"
        person = Person.objects.first()
        person.address = Address(city="Londinium")
        person.save()
        assert Person.objects.first().address.city == "Londinium"
        person = Person.objects.first()
        person.age = 35
        person.save()
        assert Person.objects.first().age == 35
    def test_dynamic_embedded_works_with_only(self):
        """Ensure custom fieldnames on a dynamic embedded document are found by qs.only()"""
        class Address(DynamicEmbeddedDocument):
            city = StringField()
        class Person(DynamicDocument):
            address = EmbeddedDocumentField(Address)
        Person.drop_collection()
        Person(
            name="Eric", address=Address(city="San Francisco", street_number="1337")
        ).save()
        assert Person.objects.first().address.street_number == "1337"
        assert (
            Person.objects.only("address__street_number").first().address.street_number
            == "1337"
        )
    def test_dynamic_and_embedded_dict_access(self):
        """Ensure embedded dynamic documents work with dict[] style access"""
        class Address(EmbeddedDocument):
            city = StringField()
        class Person(DynamicDocument):
            name = StringField()
        Person.drop_collection()
        Person(name="Ross", address=Address(city="London")).save()
        person = Person.objects.first()
        person.attrval = "This works"
        person["phone"] = "555-1212"  # but this should too
        # Same thing two levels deep
        person["address"]["city"] = "Lundenne"
        person.save()
        assert Person.objects.first().address.city == "Lundenne"
        assert Person.objects.first().phone == "555-1212"
        person = Person.objects.first()
        person.address = Address(city="Londinium")
        person.save()
        assert Person.objects.first().address.city == "Londinium"
        person = Person.objects.first()
        person["age"] = 35
        person.save()
        assert Person.objects.first().age == 35
 if __name__ == "__main__":
    unittest.main()
--- a/tests/document/test_indexes.py
+++ b/tests/document/test_indexes.py
--- a/tests/document/test_inheritance.py
+++ b/tests/document/test_inheritance.py
@ -1,617 +0,0 @@
 import unittest
 import warnings
 import pytest
 from mongoengine import (
    BooleanField,
    Document,
    EmbeddedDocument,
    EmbeddedDocumentField,
    GenericReferenceField,
    IntField,
    ReferenceField,
    StringField,
 )
 from mongoengine.pymongo_support import list_collection_names
 from tests.fixtures import Base
 from tests.utils import MongoDBTestCase
 class TestInheritance(MongoDBTestCase):
    def tearDown(self):
        for collection in list_collection_names(self.db):
            self.db.drop_collection(collection)
    def test_constructor_cls(self):
        # Ensures _cls is properly set during construction
        # and when object gets reloaded (prevent regression of #1950)
        class EmbedData(EmbeddedDocument):
            data = StringField()
            meta = {"allow_inheritance": True}
        class DataDoc(Document):
            name = StringField()
            embed = EmbeddedDocumentField(EmbedData)
            meta = {"allow_inheritance": True}
        test_doc = DataDoc(name="test", embed=EmbedData(data="data"))
        assert test_doc._cls == "DataDoc"
        assert test_doc.embed._cls == "EmbedData"
        test_doc.save()
        saved_doc = DataDoc.objects.with_id(test_doc.id)
        assert test_doc._cls == saved_doc._cls
        assert test_doc.embed._cls == saved_doc.embed._cls
        test_doc.delete()
    def test_superclasses(self):
        """Ensure that the correct list of superclasses is assembled."""
        class Animal(Document):
            meta = {"allow_inheritance": True}
        class Fish(Animal):
            pass
        class Guppy(Fish):
            pass
        class Mammal(Animal):
            pass
        class Dog(Mammal):
            pass
        class Human(Mammal):
            pass
        assert Animal._superclasses == ()
        assert Fish._superclasses == ("Animal",)
        assert Guppy._superclasses == ("Animal", "Animal.Fish")
        assert Mammal._superclasses == ("Animal",)
        assert Dog._superclasses == ("Animal", "Animal.Mammal")
        assert Human._superclasses == ("Animal", "Animal.Mammal")
    def test_external_superclasses(self):
        """Ensure that the correct list of super classes is assembled when
        importing part of the model.
        """
        class Animal(Base):
            pass
        class Fish(Animal):
            pass
        class Guppy(Fish):
            pass
        class Mammal(Animal):
            pass
        class Dog(Mammal):
            pass
        class Human(Mammal):
            pass
        assert Animal._superclasses == ("Base",)
        assert Fish._superclasses == ("Base", "Base.Animal")
        assert Guppy._superclasses == ("Base", "Base.Animal", "Base.Animal.Fish")
        assert Mammal._superclasses == ("Base", "Base.Animal")
        assert Dog._superclasses == ("Base", "Base.Animal", "Base.Animal.Mammal")
        assert Human._superclasses == ("Base", "Base.Animal", "Base.Animal.Mammal")
    def test_subclasses(self):
        """Ensure that the correct list of _subclasses (subclasses) is
        assembled.
        """
        class Animal(Document):
            meta = {"allow_inheritance": True}
        class Fish(Animal):
            pass
        class Guppy(Fish):
            pass
        class Mammal(Animal):
            pass
        class Dog(Mammal):
            pass
        class Human(Mammal):
            pass
        assert Animal._subclasses == (
            "Animal",
            "Animal.Fish",
            "Animal.Fish.Guppy",
            "Animal.Mammal",
            "Animal.Mammal.Dog",
            "Animal.Mammal.Human",
        )
        assert Fish._subclasses == ("Animal.Fish", "Animal.Fish.Guppy")
        assert Guppy._subclasses == ("Animal.Fish.Guppy",)
        assert Mammal._subclasses == (
            "Animal.Mammal",
            "Animal.Mammal.Dog",
            "Animal.Mammal.Human",
        )
        assert Human._subclasses == ("Animal.Mammal.Human",)
    def test_external_subclasses(self):
        """Ensure that the correct list of _subclasses (subclasses) is
        assembled when importing part of the model.
        """
        class Animal(Base):
            pass
        class Fish(Animal):
            pass
        class Guppy(Fish):
            pass
        class Mammal(Animal):
            pass
        class Dog(Mammal):
            pass
        class Human(Mammal):
            pass
        assert Animal._subclasses == (
            "Base.Animal",
            "Base.Animal.Fish",
            "Base.Animal.Fish.Guppy",
            "Base.Animal.Mammal",
            "Base.Animal.Mammal.Dog",
            "Base.Animal.Mammal.Human",
        )
        assert Fish._subclasses == ("Base.Animal.Fish", "Base.Animal.Fish.Guppy")
        assert Guppy._subclasses == ("Base.Animal.Fish.Guppy",)
        assert Mammal._subclasses == (
            "Base.Animal.Mammal",
            "Base.Animal.Mammal.Dog",
            "Base.Animal.Mammal.Human",
        )
        assert Human._subclasses == ("Base.Animal.Mammal.Human",)
    def test_dynamic_declarations(self):
        """Test that declaring an extra class updates meta data"""
        class Animal(Document):
            meta = {"allow_inheritance": True}
        assert Animal._superclasses == ()
        assert Animal._subclasses == ("Animal",)
        # Test dynamically adding a class changes the meta data
        class Fish(Animal):
            pass
        assert Animal._superclasses == ()
        assert Animal._subclasses == ("Animal", "Animal.Fish")
        assert Fish._superclasses == ("Animal",)
        assert Fish._subclasses == ("Animal.Fish",)
        # Test dynamically adding an inherited class changes the meta data
        class Pike(Fish):
            pass
        assert Animal._superclasses == ()
        assert Animal._subclasses == ("Animal", "Animal.Fish", "Animal.Fish.Pike")
        assert Fish._superclasses == ("Animal",)
        assert Fish._subclasses == ("Animal.Fish", "Animal.Fish.Pike")
        assert Pike._superclasses == ("Animal", "Animal.Fish")
        assert Pike._subclasses == ("Animal.Fish.Pike",)
    def test_inheritance_meta_data(self):
        """Ensure that document may inherit fields from a superclass document."""
        class Person(Document):
            name = StringField()
            age = IntField()
            meta = {"allow_inheritance": True}
        class Employee(Person):
            salary = IntField()
        assert ["_cls", "age", "id", "name", "salary"] == sorted(
            Employee._fields.keys()
        )
        assert Employee._get_collection_name() == Person._get_collection_name()
    def test_inheritance_to_mongo_keys(self):
        """Ensure that document may inherit fields from a superclass document."""
        class Person(Document):
            name = StringField()
            age = IntField()
            meta = {"allow_inheritance": True}
        class Employee(Person):
            salary = IntField()
        assert ["_cls", "age", "id", "name", "salary"] == sorted(
            Employee._fields.keys()
        )
        assert Person(name="Bob", age=35).to_mongo().keys() == ["_cls", "name", "age"]
        assert Employee(name="Bob", age=35, salary=0).to_mongo().keys() == [
            "_cls",
            "name",
            "age",
            "salary",
        ]
        assert Employee._get_collection_name() == Person._get_collection_name()
    def test_indexes_and_multiple_inheritance(self):
        """Ensure that all of the indexes are created for a document with
        multiple inheritance.
        """
        class A(Document):
            a = StringField()
            meta = {"allow_inheritance": True, "indexes": ["a"]}
        class B(Document):
            b = StringField()
            meta = {"allow_inheritance": True, "indexes": ["b"]}
        class C(A, B):
            pass
        A.drop_collection()
        B.drop_collection()
        C.drop_collection()
        C.ensure_indexes()
        assert sorted(
            idx["key"] for idx in C._get_collection().index_information().values()
        ) == sorted([[("_cls", 1), ("b", 1)], [("_id", 1)], [("_cls", 1), ("a", 1)]])
    def test_polymorphic_queries(self):
        """Ensure that the correct subclasses are returned from a query"""
        class Animal(Document):
            meta = {"allow_inheritance": True}
        class Fish(Animal):
            pass
        class Mammal(Animal):
            pass
        class Dog(Mammal):
            pass
        class Human(Mammal):
            pass
        Animal.drop_collection()
        Animal().save()
        Fish().save()
        Mammal().save()
        Dog().save()
        Human().save()
        classes = [obj.__class__ for obj in Animal.objects]
        assert classes == [Animal, Fish, Mammal, Dog, Human]
        classes = [obj.__class__ for obj in Mammal.objects]
        assert classes == [Mammal, Dog, Human]
        classes = [obj.__class__ for obj in Human.objects]
        assert classes == [Human]
    def test_allow_inheritance(self):
        """Ensure that inheritance is disabled by default on simple
        classes and that _cls will not be used.
        """
        class Animal(Document):
            name = StringField()
        # can't inherit because Animal didn't explicitly allow inheritance
        with pytest.raises(ValueError, match="Document Animal may not be subclassed"):
            class Dog(Animal):
                pass
        # Check that _cls etc aren't present on simple documents
        dog = Animal(name="dog").save()
        assert dog.to_mongo().keys() == ["_id", "name"]
        collection = self.db[Animal._get_collection_name()]
        obj = collection.find_one()
        assert "_cls" not in obj
    def test_cant_turn_off_inheritance_on_subclass(self):
        """Ensure if inheritance is on in a subclass you cant turn it off."""
        class Animal(Document):
            name = StringField()
            meta = {"allow_inheritance": True}
        with pytest.raises(ValueError) as exc_info:
            class Mammal(Animal):
                meta = {"allow_inheritance": False}
        assert (
            str(exc_info.value)
            == 'Only direct subclasses of Document may set "allow_inheritance" to False'
        )
    def test_allow_inheritance_abstract_document(self):
        """Ensure that abstract documents can set inheritance rules and that
        _cls will not be used.
        """
        class FinalDocument(Document):
            meta = {"abstract": True, "allow_inheritance": False}
        class Animal(FinalDocument):
            name = StringField()
        with pytest.raises(ValueError):
            class Mammal(Animal):
                pass
        # Check that _cls isn't present in simple documents
        doc = Animal(name="dog")
        assert "_cls" not in doc.to_mongo()
    def test_using_abstract_class_in_reference_field(self):
        # Ensures no regression of #1920
        class AbstractHuman(Document):
            meta = {"abstract": True}
        class Dad(AbstractHuman):
            name = StringField()
        class Home(Document):
            dad = ReferenceField(AbstractHuman)  # Referencing the abstract class
            address = StringField()
        dad = Dad(name="5").save()
        Home(dad=dad, address="street").save()
        home = Home.objects.first()
        home.address = "garbage"
        home.save()  # Was failing with ValidationError
    def test_abstract_class_referencing_self(self):
        # Ensures no regression of #1920
        class Human(Document):
            meta = {"abstract": True}
            creator = ReferenceField("self", dbref=True)
        class User(Human):
            name = StringField()
        user = User(name="John").save()
        user2 = User(name="Foo", creator=user).save()
        user2 = User.objects.with_id(user2.id)
        user2.name = "Bar"
        user2.save()  # Was failing with ValidationError
    def test_abstract_handle_ids_in_metaclass_properly(self):
        class City(Document):
            continent = StringField()
            meta = {"abstract": True, "allow_inheritance": False}
        class EuropeanCity(City):
            name = StringField()
        berlin = EuropeanCity(name="Berlin", continent="Europe")
        assert len(berlin._db_field_map) == len(berlin._fields_ordered)
        assert len(berlin._reverse_db_field_map) == len(berlin._fields_ordered)
        assert len(berlin._fields_ordered) == 3
        assert berlin._fields_ordered[0] == "id"
    def test_auto_id_not_set_if_specific_in_parent_class(self):
        class City(Document):
            continent = StringField()
            city_id = IntField(primary_key=True)
            meta = {"abstract": True, "allow_inheritance": False}
        class EuropeanCity(City):
            name = StringField()
        berlin = EuropeanCity(name="Berlin", continent="Europe")
        assert len(berlin._db_field_map) == len(berlin._fields_ordered)
        assert len(berlin._reverse_db_field_map) == len(berlin._fields_ordered)
        assert len(berlin._fields_ordered) == 3
        assert berlin._fields_ordered[0] == "city_id"
    def test_auto_id_vs_non_pk_id_field(self):
        class City(Document):
            continent = StringField()
            id = IntField()
            meta = {"abstract": True, "allow_inheritance": False}
        class EuropeanCity(City):
            name = StringField()
        berlin = EuropeanCity(name="Berlin", continent="Europe")
        assert len(berlin._db_field_map) == len(berlin._fields_ordered)
        assert len(berlin._reverse_db_field_map) == len(berlin._fields_ordered)
        assert len(berlin._fields_ordered) == 4
        assert berlin._fields_ordered[0] == "auto_id_0"
        berlin.save()
        assert berlin.pk == berlin.auto_id_0
    def test_abstract_document_creation_does_not_fail(self):
        class City(Document):
            continent = StringField()
            meta = {"abstract": True, "allow_inheritance": False}
        city = City(continent="asia")
        assert city.pk is None
        # TODO: expected error? Shouldn't we create a new error type?
        with pytest.raises(KeyError):
            city.pk = 1
    def test_allow_inheritance_embedded_document(self):
        """Ensure embedded documents respect inheritance."""
        class Comment(EmbeddedDocument):
            content = StringField()
        with pytest.raises(ValueError):
            class SpecialComment(Comment):
                pass
        doc = Comment(content="test")
        assert "_cls" not in doc.to_mongo()
        class Comment(EmbeddedDocument):
            content = StringField()
            meta = {"allow_inheritance": True}
        doc = Comment(content="test")
        assert "_cls" in doc.to_mongo()
    def test_document_inheritance(self):
        """Ensure mutliple inheritance of abstract documents"""
        class DateCreatedDocument(Document):
            meta = {"allow_inheritance": True, "abstract": True}
        class DateUpdatedDocument(Document):
            meta = {"allow_inheritance": True, "abstract": True}
        class MyDocument(DateCreatedDocument, DateUpdatedDocument):
            pass
    def test_abstract_documents(self):
        """Ensure that a document superclass can be marked as abstract
        thereby not using it as the name for the collection."""
        defaults = {
            "index_background": True,
            "index_opts": {"hello": "world"},
            "allow_inheritance": True,
            "queryset_class": "QuerySet",
            "db_alias": "myDB",
            "shard_key": ("hello", "world"),
        }
        meta_settings = {"abstract": True}
        meta_settings.update(defaults)
        class Animal(Document):
            name = StringField()
            meta = meta_settings
        class Fish(Animal):
            pass
        class Guppy(Fish):
            pass
        class Mammal(Animal):
            meta = {"abstract": True}
        class Human(Mammal):
            pass
        for k, v in defaults.items():
            for cls in [Animal, Fish, Guppy]:
                assert cls._meta[k] == v
        assert "collection" not in Animal._meta
        assert "collection" not in Mammal._meta
        assert Animal._get_collection_name() is None
        assert Mammal._get_collection_name() is None
        assert Fish._get_collection_name() == "fish"
        assert Guppy._get_collection_name() == "fish"
        assert Human._get_collection_name() == "human"
        # ensure that a subclass of a non-abstract class can't be abstract
        with pytest.raises(ValueError):
            class EvilHuman(Human):
                evil = BooleanField(default=True)
                meta = {"abstract": True}
    def test_abstract_embedded_documents(self):
        # 789: EmbeddedDocument shouldn't inherit abstract
        class A(EmbeddedDocument):
            meta = {"abstract": True}
        class B(A):
            pass
        assert not B._meta["abstract"]
    def test_inherited_collections(self):
        """Ensure that subclassed documents don't override parents'
        collections
        """
        class Drink(Document):
            name = StringField()
            meta = {"allow_inheritance": True}
        class Drinker(Document):
            drink = GenericReferenceField()
        try:
            warnings.simplefilter("error")
            class AcloholicDrink(Drink):
                meta = {"collection": "booze"}
        except SyntaxWarning:
            warnings.simplefilter("ignore")
            class AlcoholicDrink(Drink):
                meta = {"collection": "booze"}
        else:
            raise AssertionError("SyntaxWarning should be triggered")
        warnings.resetwarnings()
        Drink.drop_collection()
        AlcoholicDrink.drop_collection()
        Drinker.drop_collection()
        red_bull = Drink(name="Red Bull")
        red_bull.save()
        programmer = Drinker(drink=red_bull)
        programmer.save()
        beer = AlcoholicDrink(name="Beer")
        beer.save()
        real_person = Drinker(drink=beer)
        real_person.save()
        assert Drinker.objects[0].drink.name == red_bull.name
        assert Drinker.objects[1].drink.name == beer.name
 if __name__ == "__main__":
    unittest.main()
--- a/tests/document/test_instance.py
+++ b/tests/document/test_instance.py
--- a/tests/document/test_json_serialisation.py
+++ b/tests/document/test_json_serialisation.py
@ -1,106 +0,0 @@
 import unittest
 import uuid
 from datetime import datetime
 from bson import ObjectId
 from mongoengine import *
 from tests.utils import MongoDBTestCase
 class TestJson(MongoDBTestCase):
    def test_json_names(self):
        """
        Going to test reported issue:
            https://github.com/MongoEngine/mongoengine/issues/654
        where the reporter asks for the availability to perform
        a to_json with the original class names and not the abreviated
        mongodb document keys
        """
        class Embedded(EmbeddedDocument):
            string = StringField(db_field="s")
        class Doc(Document):
            string = StringField(db_field="s")
            embedded = EmbeddedDocumentField(Embedded, db_field="e")
        doc = Doc(string="Hello", embedded=Embedded(string="Inner Hello"))
        doc_json = doc.to_json(
            sort_keys=True, use_db_field=False, separators=(",", ":")
        )
        expected_json = """{"embedded":{"string":"Inner Hello"},"string":"Hello"}"""
        assert doc_json == expected_json
    def test_json_simple(self):
        class Embedded(EmbeddedDocument):
            string = StringField()
        class Doc(Document):
            string = StringField()
            embedded_field = EmbeddedDocumentField(Embedded)
            def __eq__(self, other):
                return (
                    self.string == other.string
                    and self.embedded_field == other.embedded_field
                )
        doc = Doc(string="Hi", embedded_field=Embedded(string="Hi"))
        doc_json = doc.to_json(sort_keys=True, separators=(",", ":"))
        expected_json = """{"embedded_field":{"string":"Hi"},"string":"Hi"}"""
        assert doc_json == expected_json
        assert doc == Doc.from_json(doc.to_json())
    def test_json_complex(self):
        class EmbeddedDoc(EmbeddedDocument):
            pass
        class Simple(Document):
            pass
        class Doc(Document):
            string_field = StringField(default="1")
            int_field = IntField(default=1)
            float_field = FloatField(default=1.1)
            boolean_field = BooleanField(default=True)
            datetime_field = DateTimeField(default=datetime.now)
            embedded_document_field = EmbeddedDocumentField(
                EmbeddedDoc, default=lambda: EmbeddedDoc()
            )
            list_field = ListField(default=lambda: [1, 2, 3])
            dict_field = DictField(default=lambda: {"hello": "world"})
            objectid_field = ObjectIdField(default=ObjectId)
            reference_field = ReferenceField(Simple, default=lambda: Simple().save())
            map_field = MapField(IntField(), default=lambda: {"simple": 1})
            decimal_field = DecimalField(default=1.0)
            complex_datetime_field = ComplexDateTimeField(default=datetime.now)
            url_field = URLField(default="http://mongoengine.org")
            dynamic_field = DynamicField(default=1)
            generic_reference_field = GenericReferenceField(
                default=lambda: Simple().save()
            )
            sorted_list_field = SortedListField(IntField(), default=lambda: [1, 2, 3])
            email_field = EmailField(default="ross@example.com")
            geo_point_field = GeoPointField(default=lambda: [1, 2])
            sequence_field = SequenceField()
            uuid_field = UUIDField(default=uuid.uuid4)
            generic_embedded_document_field = GenericEmbeddedDocumentField(
                default=lambda: EmbeddedDoc()
            )
            def __eq__(self, other):
                import json
                return json.loads(self.to_json()) == json.loads(other.to_json())
        doc = Doc()
        assert doc == Doc.from_json(doc.to_json())
 if __name__ == "__main__":
    unittest.main()
--- a/tests/document/test_validation.py
+++ b/tests/document/test_validation.py
@ -1,217 +0,0 @@
 import unittest
 from datetime import datetime
 import pytest
 from mongoengine import *
 from tests.utils import MongoDBTestCase
 class TestValidatorError(MongoDBTestCase):
    def test_to_dict(self):
        """Ensure a ValidationError handles error to_dict correctly."""
        error = ValidationError("root")
        assert error.to_dict() == {}
        # 1st level error schema
        error.errors = {"1st": ValidationError("bad 1st")}
        assert "1st" in error.to_dict()
        assert error.to_dict()["1st"] == "bad 1st"
        # 2nd level error schema
        error.errors = {
            "1st": ValidationError(
                "bad 1st", errors={"2nd": ValidationError("bad 2nd")}
            )
        }
        assert "1st" in error.to_dict()
        assert isinstance(error.to_dict()["1st"], dict)
        assert "2nd" in error.to_dict()["1st"]
        assert error.to_dict()["1st"]["2nd"] == "bad 2nd"
        # moar levels
        error.errors = {
            "1st": ValidationError(
                "bad 1st",
                errors={
                    "2nd": ValidationError(
                        "bad 2nd",
                        errors={
                            "3rd": ValidationError(
                                "bad 3rd", errors={"4th": ValidationError("Inception")}
                            )
                        },
                    )
                },
            )
        }
        assert "1st" in error.to_dict()
        assert "2nd" in error.to_dict()["1st"]
        assert "3rd" in error.to_dict()["1st"]["2nd"]
        assert "4th" in error.to_dict()["1st"]["2nd"]["3rd"]
        assert error.to_dict()["1st"]["2nd"]["3rd"]["4th"] == "Inception"
        assert error.message == "root(2nd.3rd.4th.Inception: ['1st'])"
    def test_model_validation(self):
        class User(Document):
            username = StringField(primary_key=True)
            name = StringField(required=True)
        try:
            User().validate()
        except ValidationError as e:
            assert "User:None" in e.message
            assert e.to_dict() == {
                "username": "Field is required",
                "name": "Field is required",
            }
        user = User(username="RossC0", name="Ross").save()
        user.name = None
        try:
            user.save()
        except ValidationError as e:
            assert "User:RossC0" in e.message
            assert e.to_dict() == {"name": "Field is required"}
    def test_fields_rewrite(self):
        class BasePerson(Document):
            name = StringField()
            age = IntField()
            meta = {"abstract": True}
        class Person(BasePerson):
            name = StringField(required=True)
        p = Person(age=15)
        with pytest.raises(ValidationError):
            p.validate()
    def test_embedded_document_validation(self):
        """Ensure that embedded documents may be validated."""
        class Comment(EmbeddedDocument):
            date = DateTimeField()
            content = StringField(required=True)
        comment = Comment()
        with pytest.raises(ValidationError):
            comment.validate()
        comment.content = "test"
        comment.validate()
        comment.date = 4
        with pytest.raises(ValidationError):
            comment.validate()
        comment.date = datetime.now()
        comment.validate()
        assert comment._instance is None
    def test_embedded_db_field_validate(self):
        class SubDoc(EmbeddedDocument):
            val = IntField(required=True)
        class Doc(Document):
            id = StringField(primary_key=True)
            e = EmbeddedDocumentField(SubDoc, db_field="eb")
        try:
            Doc(id="bad").validate()
        except ValidationError as e:
            assert "SubDoc:None" in e.message
            assert e.to_dict() == {"e": {"val": "OK could not be converted to int"}}
        Doc.drop_collection()
        Doc(id="test", e=SubDoc(val=15)).save()
        doc = Doc.objects.first()
        keys = doc._data.keys()
        assert 2 == len(keys)
        assert "e" in keys
        assert "id" in keys
        doc.e.val = "OK"
        try:
            doc.save()
        except ValidationError as e:
            assert "Doc:test" in e.message
            assert e.to_dict() == {"e": {"val": "OK could not be converted to int"}}
    def test_embedded_weakref(self):
        class SubDoc(EmbeddedDocument):
            val = IntField(required=True)
        class Doc(Document):
            e = EmbeddedDocumentField(SubDoc, db_field="eb")
        Doc.drop_collection()
        d1 = Doc()
        d2 = Doc()
        s = SubDoc()
        with pytest.raises(ValidationError):
            s.validate()
        d1.e = s
        d2.e = s
        del d1
        with pytest.raises(ValidationError):
            d2.validate()
    def test_parent_reference_in_child_document(self):
        """
        Test to ensure a ReferenceField can store a reference to a parent
        class when inherited. Issue #954.
        """
        class Parent(Document):
            meta = {"allow_inheritance": True}
            reference = ReferenceField("self")
        class Child(Parent):
            pass
        parent = Parent()
        parent.save()
        child = Child(reference=parent)
        # Saving child should not raise a ValidationError
        try:
            child.save()
        except ValidationError as e:
            self.fail("ValidationError raised: %s" % e.message)
    def test_parent_reference_set_as_attribute_in_child_document(self):
        """
        Test to ensure a ReferenceField can store a reference to a parent
        class when inherited and when set via attribute. Issue #954.
        """
        class Parent(Document):
            meta = {"allow_inheritance": True}
            reference = ReferenceField("self")
        class Child(Parent):
            pass
        parent = Parent()
        parent.save()
        child = Child()
        child.reference = parent
        # Saving the child should not raise a ValidationError
        child.save()
 if __name__ == "__main__":
    unittest.main()
--- a/tests/fields/init.py
+++ b/tests/fields/init.py
--- a/tests/fields/mongodb_leaf.png
+++ b/tests/fields/mongodb_leaf.png
--- a/tests/fields/test_binary_field.py
+++ b/tests/fields/test_binary_field.py
@ -1,140 +0,0 @@
 import uuid
 import pytest
 from bson import Binary
 from mongoengine import *
 from tests.utils import MongoDBTestCase
 BIN_VALUE = "\xa9\xf3\x8d(\xd7\x03\x84\xb4k[\x0f\xe3\xa2\x19\x85p[J\xa3\xd2>\xde\xe6\x87\xb1\x7f\xc6\xe6\xd9r\x18\xf5".encode(
    "latin-1"
 )
 class TestBinaryField(MongoDBTestCase):
    def test_binary_fields(self):
        """Ensure that binary fields can be stored and retrieved."""
        class Attachment(Document):
            content_type = StringField()
            blob = BinaryField()
        BLOB = b"\xe6\x00\xc4\xff\x07"
        MIME_TYPE = "application/octet-stream"
        Attachment.drop_collection()
        attachment = Attachment(content_type=MIME_TYPE, blob=BLOB)
        attachment.save()
        attachment_1 = Attachment.objects().first()
        assert MIME_TYPE == attachment_1.content_type
        assert BLOB == bytes(attachment_1.blob)
    def test_validation_succeeds(self):
        """Ensure that valid values can be assigned to binary fields."""
        class AttachmentRequired(Document):
            blob = BinaryField(required=True)
        class AttachmentSizeLimit(Document):
            blob = BinaryField(max_bytes=4)
        attachment_required = AttachmentRequired()
        with pytest.raises(ValidationError):
            attachment_required.validate()
        attachment_required.blob = Binary(b"\xe6\x00\xc4\xff\x07")
        attachment_required.validate()
        _5_BYTES = b"\xe6\x00\xc4\xff\x07"
        _4_BYTES = b"\xe6\x00\xc4\xff"
        with pytest.raises(ValidationError):
            AttachmentSizeLimit(blob=_5_BYTES).validate()
        AttachmentSizeLimit(blob=_4_BYTES).validate()
    def test_validation_fails(self):
        """Ensure that invalid values cannot be assigned to binary fields."""
        class Attachment(Document):
            blob = BinaryField()
        for invalid_data in (2, "Im_a_unicode", ["some_str"]):
            with pytest.raises(ValidationError):
                Attachment(blob=invalid_data).validate()
    def test__primary(self):
        class Attachment(Document):
            id = BinaryField(primary_key=True)
        Attachment.drop_collection()
        binary_id = uuid.uuid4().bytes
        att = Attachment(id=binary_id).save()
        assert 1 == Attachment.objects.count()
        assert 1 == Attachment.objects.filter(id=att.id).count()
        att.delete()
        assert 0 == Attachment.objects.count()
    def test_primary_filter_by_binary_pk_as_str(self):
        class Attachment(Document):
            id = BinaryField(primary_key=True)
        Attachment.drop_collection()
        binary_id = uuid.uuid4().bytes
        att = Attachment(id=binary_id).save()
        assert 1 == Attachment.objects.filter(id=binary_id).count()
        att.delete()
        assert 0 == Attachment.objects.count()
    def test_match_querying_with_bytes(self):
        class MyDocument(Document):
            bin_field = BinaryField()
        MyDocument.drop_collection()
        doc = MyDocument(bin_field=BIN_VALUE).save()
        matched_doc = MyDocument.objects(bin_field=BIN_VALUE).first()
        assert matched_doc.id == doc.id
    def test_match_querying_with_binary(self):
        class MyDocument(Document):
            bin_field = BinaryField()
        MyDocument.drop_collection()
        doc = MyDocument(bin_field=BIN_VALUE).save()
        matched_doc = MyDocument.objects(bin_field=Binary(BIN_VALUE)).first()
        assert matched_doc.id == doc.id
    def test_modify_operation__set(self):
        """Ensures no regression of bug #1127"""
        class MyDocument(Document):
            some_field = StringField()
            bin_field = BinaryField()
        MyDocument.drop_collection()
        doc = MyDocument.objects(some_field="test").modify(
            upsert=True, new=True, set__bin_field=BIN_VALUE
        )
        assert doc.some_field == "test"
        assert doc.bin_field == BIN_VALUE
    def test_update_one(self):
        """Ensures no regression of bug #1127"""
        class MyDocument(Document):
            bin_field = BinaryField()
        MyDocument.drop_collection()
        bin_data = b"\xe6\x00\xc4\xff\x07"
        doc = MyDocument(bin_field=bin_data).save()
        n_updated = MyDocument.objects(bin_field=bin_data).update_one(
            bin_field=BIN_VALUE
        )
        assert n_updated == 1
        fetched = MyDocument.objects.with_id(doc.id)
        assert fetched.bin_field == BIN_VALUE
--- a/tests/fields/test_boolean_field.py
+++ b/tests/fields/test_boolean_field.py
@ -1,62 +0,0 @@
 import pytest
 from mongoengine import *
 from tests.utils import MongoDBTestCase, get_as_pymongo
 class TestBooleanField(MongoDBTestCase):
    def test_storage(self):
        class Person(Document):
            admin = BooleanField()
        person = Person(admin=True)
        person.save()
        assert get_as_pymongo(person) == {"_id": person.id, "admin": True}
    def test_construction_does_not_fail_uncastable_value(self):
        class BoolFail:
            def __bool__(self):
                return "bogus"
        class Person(Document):
            admin = BooleanField()
        person = Person(admin=BoolFail())
        person.admin == "bogus"
    def test_validation(self):
        """Ensure that invalid values cannot be assigned to boolean
        fields.
        """
        class Person(Document):
            admin = BooleanField()
        person = Person()
        person.admin = True
        person.validate()
        person.admin = 2
        with pytest.raises(ValidationError):
            person.validate()
        person.admin = "Yes"
        with pytest.raises(ValidationError):
            person.validate()
        person.admin = "False"
        with pytest.raises(ValidationError):
            person.validate()
    def test_weirdness_constructor(self):
        """When attribute is set in contructor, it gets cast into a bool
        which causes some weird behavior. We dont necessarily want to maintain this behavior
        but its a known issue
        """
        class Person(Document):
            admin = BooleanField()
        new_person = Person(admin="False")
        assert new_person.admin
        new_person = Person(admin="0")
        assert new_person.admin
--- a/tests/fields/test_cached_reference_field.py
+++ b/tests/fields/test_cached_reference_field.py
@ -1,393 +0,0 @@
 from decimal import Decimal
 import pytest
 from mongoengine import (
    CachedReferenceField,
    DecimalField,
    Document,
    EmbeddedDocument,
    EmbeddedDocumentField,
    InvalidDocumentError,
    ListField,
    ReferenceField,
    StringField,
    ValidationError,
 )
 from tests.utils import MongoDBTestCase
 class TestCachedReferenceField(MongoDBTestCase):
    def test_constructor_fail_bad_document_type(self):
        with pytest.raises(
            ValidationError, match="must be a document class or a string"
        ):
            CachedReferenceField(document_type=0)
    def test_get_and_save(self):
        """
        Tests #1047: CachedReferenceField creates DBRefs on to_python,
        but can't save them on to_mongo.
        """
        class Animal(Document):
            name = StringField()
            tag = StringField()
        class Ocorrence(Document):
            person = StringField()
            animal = CachedReferenceField(Animal)
        Animal.drop_collection()
        Ocorrence.drop_collection()
        Ocorrence(
            person="testte", animal=Animal(name="Leopard", tag="heavy").save()
        ).save()
        p = Ocorrence.objects.get()
        p.person = "new_testte"
        p.save()
    def test_general_things(self):
        class Animal(Document):
            name = StringField()
            tag = StringField()
        class Ocorrence(Document):
            person = StringField()
            animal = CachedReferenceField(Animal, fields=["tag"])
        Animal.drop_collection()
        Ocorrence.drop_collection()
        a = Animal(name="Leopard", tag="heavy")
        a.save()
        assert Animal._cached_reference_fields == [Ocorrence.animal]
        o = Ocorrence(person="teste", animal=a)
        o.save()
        p = Ocorrence(person="Wilson")
        p.save()
        assert Ocorrence.objects(animal=None).count() == 1
        assert a.to_mongo(fields=["tag"]) == {"tag": "heavy", "_id": a.pk}
        assert o.to_mongo()["animal"]["tag"] == "heavy"
        # counts
        Ocorrence(person="teste 2").save()
        Ocorrence(person="teste 3").save()
        count = Ocorrence.objects(animal__tag="heavy").count()
        assert count == 1
        ocorrence = Ocorrence.objects(animal__tag="heavy").first()
        assert ocorrence.person == "teste"
        assert isinstance(ocorrence.animal, Animal)
    def test_with_decimal(self):
        class PersonAuto(Document):
            name = StringField()
            salary = DecimalField()
        class SocialTest(Document):
            group = StringField()
            person = CachedReferenceField(PersonAuto, fields=("salary",))
        PersonAuto.drop_collection()
        SocialTest.drop_collection()
        p = PersonAuto(name="Alberto", salary=Decimal("7000.00"))
        p.save()
        s = SocialTest(group="dev", person=p)
        s.save()
        assert SocialTest.objects._collection.find_one({"person.salary": 7000.00}) == {
            "_id": s.pk,
            "group": s.group,
            "person": {"_id": p.pk, "salary": 7000.00},
        }
    def test_cached_reference_field_reference(self):
        class Group(Document):
            name = StringField()
        class Person(Document):
            name = StringField()
            group = ReferenceField(Group)
        class SocialData(Document):
            obs = StringField()
            tags = ListField(StringField())
            person = CachedReferenceField(Person, fields=("group",))
        Group.drop_collection()
        Person.drop_collection()
        SocialData.drop_collection()
        g1 = Group(name="dev")
        g1.save()
        g2 = Group(name="designers")
        g2.save()
        p1 = Person(name="Alberto", group=g1)
        p1.save()
        p2 = Person(name="Andre", group=g1)
        p2.save()
        p3 = Person(name="Afro design", group=g2)
        p3.save()
        s1 = SocialData(obs="testing 123", person=p1, tags=["tag1", "tag2"])
        s1.save()
        s2 = SocialData(obs="testing 321", person=p3, tags=["tag3", "tag4"])
        s2.save()
        assert SocialData.objects._collection.find_one({"tags": "tag2"}) == {
            "_id": s1.pk,
            "obs": "testing 123",
            "tags": ["tag1", "tag2"],
            "person": {"_id": p1.pk, "group": g1.pk},
        }
        assert SocialData.objects(person__group=g2).count() == 1
        assert SocialData.objects(person__group=g2).first() == s2
    def test_cached_reference_field_push_with_fields(self):
        class Product(Document):
            name = StringField()
        Product.drop_collection()
        class Basket(Document):
            products = ListField(CachedReferenceField(Product, fields=["name"]))
        Basket.drop_collection()
        product1 = Product(name="abc").save()
        product2 = Product(name="def").save()
        basket = Basket(products=[product1]).save()
        assert Basket.objects._collection.find_one() == {
            "_id": basket.pk,
            "products": [{"_id": product1.pk, "name": product1.name}],
        }
        # push to list
        basket.update(push__products=product2)
        basket.reload()
        assert Basket.objects._collection.find_one() == {
            "_id": basket.pk,
            "products": [
                {"_id": product1.pk, "name": product1.name},
                {"_id": product2.pk, "name": product2.name},
            ],
        }
    def test_cached_reference_field_update_all(self):
        class Person(Document):
            TYPES = (("pf", "PF"), ("pj", "PJ"))
            name = StringField()
            tp = StringField(choices=TYPES)
            father = CachedReferenceField("self", fields=("tp",))
        Person.drop_collection()
        a1 = Person(name="Wilson Father", tp="pj")
        a1.save()
        a2 = Person(name="Wilson Junior", tp="pf", father=a1)
        a2.save()
        a2 = Person.objects.with_id(a2.id)
        assert a2.father.tp == a1.tp
        assert dict(a2.to_mongo()) == {
            "_id": a2.pk,
            "name": "Wilson Junior",
            "tp": "pf",
            "father": {"_id": a1.pk, "tp": "pj"},
        }
        assert Person.objects(father=a1)._query == {"father._id": a1.pk}
        assert Person.objects(father=a1).count() == 1
        Person.objects.update(set__tp="pf")
        Person.father.sync_all()
        a2.reload()
        assert dict(a2.to_mongo()) == {
            "_id": a2.pk,
            "name": "Wilson Junior",
            "tp": "pf",
            "father": {"_id": a1.pk, "tp": "pf"},
        }
    def test_cached_reference_fields_on_embedded_documents(self):
        with pytest.raises(InvalidDocumentError):
            class Test(Document):
                name = StringField()
            type(
                "WrongEmbeddedDocument",
                (EmbeddedDocument,),
                {"test": CachedReferenceField(Test)},
            )
    def test_cached_reference_auto_sync(self):
        class Person(Document):
            TYPES = (("pf", "PF"), ("pj", "PJ"))
            name = StringField()
            tp = StringField(choices=TYPES)
            father = CachedReferenceField("self", fields=("tp",))
        Person.drop_collection()
        a1 = Person(name="Wilson Father", tp="pj")
        a1.save()
        a2 = Person(name="Wilson Junior", tp="pf", father=a1)
        a2.save()
        a1.tp = "pf"
        a1.save()
        a2.reload()
        assert dict(a2.to_mongo()) == {
            "_id": a2.pk,
            "name": "Wilson Junior",
            "tp": "pf",
            "father": {"_id": a1.pk, "tp": "pf"},
        }
    def test_cached_reference_auto_sync_disabled(self):
        class Persone(Document):
            TYPES = (("pf", "PF"), ("pj", "PJ"))
            name = StringField()
            tp = StringField(choices=TYPES)
            father = CachedReferenceField("self", fields=("tp",), auto_sync=False)
        Persone.drop_collection()
        a1 = Persone(name="Wilson Father", tp="pj")
        a1.save()
        a2 = Persone(name="Wilson Junior", tp="pf", father=a1)
        a2.save()
        a1.tp = "pf"
        a1.save()
        assert Persone.objects._collection.find_one({"_id": a2.pk}) == {
            "_id": a2.pk,
            "name": "Wilson Junior",
            "tp": "pf",
            "father": {"_id": a1.pk, "tp": "pj"},
        }
    def test_cached_reference_embedded_fields(self):
        class Owner(EmbeddedDocument):
            TPS = (("n", "Normal"), ("u", "Urgent"))
            name = StringField()
            tp = StringField(verbose_name="Type", db_field="t", choices=TPS)
        class Animal(Document):
            name = StringField()
            tag = StringField()
            owner = EmbeddedDocumentField(Owner)
        class Ocorrence(Document):
            person = StringField()
            animal = CachedReferenceField(Animal, fields=["tag", "owner.tp"])
        Animal.drop_collection()
        Ocorrence.drop_collection()
        a = Animal(
            name="Leopard", tag="heavy", owner=Owner(tp="u", name="Wilson Júnior")
        )
        a.save()
        o = Ocorrence(person="teste", animal=a)
        o.save()
        assert dict(a.to_mongo(fields=["tag", "owner.tp"])) == {
            "_id": a.pk,
            "tag": "heavy",
            "owner": {"t": "u"},
        }
        assert o.to_mongo()["animal"]["tag"] == "heavy"
        assert o.to_mongo()["animal"]["owner"]["t"] == "u"
        # Check to_mongo with fields
        assert "animal" not in o.to_mongo(fields=["person"])
        # counts
        Ocorrence(person="teste 2").save()
        Ocorrence(person="teste 3").save()
        count = Ocorrence.objects(animal__tag="heavy", animal__owner__tp="u").count()
        assert count == 1
        ocorrence = Ocorrence.objects(
            animal__tag="heavy", animal__owner__tp="u"
        ).first()
        assert ocorrence.person == "teste"
        assert isinstance(ocorrence.animal, Animal)
    def test_cached_reference_embedded_list_fields(self):
        class Owner(EmbeddedDocument):
            name = StringField()
            tags = ListField(StringField())
        class Animal(Document):
            name = StringField()
            tag = StringField()
            owner = EmbeddedDocumentField(Owner)
        class Ocorrence(Document):
            person = StringField()
            animal = CachedReferenceField(Animal, fields=["tag", "owner.tags"])
        Animal.drop_collection()
        Ocorrence.drop_collection()
        a = Animal(
            name="Leopard",
            tag="heavy",
            owner=Owner(tags=["cool", "funny"], name="Wilson Júnior"),
        )
        a.save()
        o = Ocorrence(person="teste 2", animal=a)
        o.save()
        assert dict(a.to_mongo(fields=["tag", "owner.tags"])) == {
            "_id": a.pk,
            "tag": "heavy",
            "owner": {"tags": ["cool", "funny"]},
        }
        assert o.to_mongo()["animal"]["tag"] == "heavy"
        assert o.to_mongo()["animal"]["owner"]["tags"] == ["cool", "funny"]
        # counts
        Ocorrence(person="teste 2").save()
        Ocorrence(person="teste 3").save()
        query = Ocorrence.objects(
            animal__tag="heavy", animal__owner__tags="cool"
        )._query
        assert query == {"animal.owner.tags": "cool", "animal.tag": "heavy"}
        ocorrence = Ocorrence.objects(
            animal__tag="heavy", animal__owner__tags="cool"
        ).first()
        assert ocorrence.person == "teste 2"
        assert isinstance(ocorrence.animal, Animal)
--- a/tests/fields/test_complex_datetime_field.py
+++ b/tests/fields/test_complex_datetime_field.py
@ -1,208 +0,0 @@
 import datetime
 import itertools
 import math
 import re
 import pytest
 from mongoengine import *
 from tests.utils import MongoDBTestCase
 class ComplexDateTimeFieldTest(MongoDBTestCase):
    def test_complexdatetime_storage(self):
        """Tests for complex datetime fields - which can handle
        microseconds without rounding.
        """
        class LogEntry(Document):
            date = ComplexDateTimeField()
            date_with_dots = ComplexDateTimeField(separator=".")
        LogEntry.drop_collection()
        # Post UTC - microseconds are rounded (down) nearest millisecond and
        # dropped - with default datetimefields
        d1 = datetime.datetime(1970, 1, 1, 0, 0, 1, 999)
        log = LogEntry()
        log.date = d1
        log.save()
        log.reload()
        assert log.date == d1
        # Post UTC - microseconds are rounded (down) nearest millisecond - with
        # default datetimefields
        d1 = datetime.datetime(1970, 1, 1, 0, 0, 1, 9999)
        log.date = d1
        log.save()
        log.reload()
        assert log.date == d1
        # Pre UTC dates microseconds below 1000 are dropped - with default
        # datetimefields
        d1 = datetime.datetime(1969, 12, 31, 23, 59, 59, 999)
        log.date = d1
        log.save()
        log.reload()
        assert log.date == d1
        # Pre UTC microseconds above 1000 is wonky - with default datetimefields
        # log.date has an invalid microsecond value so I can't construct
        # a date to compare.
        for i in range(1001, 3113, 33):
            d1 = datetime.datetime(1969, 12, 31, 23, 59, 59, i)
            log.date = d1
            log.save()
            log.reload()
            assert log.date == d1
            log1 = LogEntry.objects.get(date=d1)
            assert log == log1
        # Test string padding
        microsecond = map(int, (math.pow(10, x) for x in range(6)))
        mm = dd = hh = ii = ss = [1, 10]
        for values in itertools.product([2014], mm, dd, hh, ii, ss, microsecond):
            stored = LogEntry(date=datetime.datetime(*values)).to_mongo()["date"]
            assert (
                re.match(r"^\d{4},\d{2},\d{2},\d{2},\d{2},\d{2},\d{6}$", stored)
                is not None
            )
        # Test separator
        stored = LogEntry(date_with_dots=datetime.datetime(2014, 1, 1)).to_mongo()[
            "date_with_dots"
        ]
        assert (
            re.match(r"^\d{4}.\d{2}.\d{2}.\d{2}.\d{2}.\d{2}.\d{6}$", stored) is not None
        )
    def test_complexdatetime_usage(self):
        """Tests for complex datetime fields - which can handle
        microseconds without rounding.
        """
        class LogEntry(Document):
            date = ComplexDateTimeField()
        LogEntry.drop_collection()
        d1 = datetime.datetime(1950, 1, 1, 0, 0, 1, 999)
        log = LogEntry()
        log.date = d1
        log.save()
        log1 = LogEntry.objects.get(date=d1)
        assert log == log1
        # create extra 59 log entries for a total of 60
        for i in range(1951, 2010):
            d = datetime.datetime(i, 1, 1, 0, 0, 1, 999)
            LogEntry(date=d).save()
        assert LogEntry.objects.count() == 60
        # Test ordering
        logs = LogEntry.objects.order_by("date")
        i = 0
        while i < 59:
            assert logs[i].date <= logs[i + 1].date
            i += 1
        logs = LogEntry.objects.order_by("-date")
        i = 0
        while i < 59:
            assert logs[i].date >= logs[i + 1].date
            i += 1
        # Test searching
        logs = LogEntry.objects.filter(date__gte=datetime.datetime(1980, 1, 1))
        assert logs.count() == 30
        logs = LogEntry.objects.filter(date__lte=datetime.datetime(1980, 1, 1))
        assert logs.count() == 30
        logs = LogEntry.objects.filter(
            date__lte=datetime.datetime(2011, 1, 1),
            date__gte=datetime.datetime(2000, 1, 1),
        )
        assert logs.count() == 10
        LogEntry.drop_collection()
        # Test microsecond-level ordering/filtering
        for microsecond in (99, 999, 9999, 10000):
            LogEntry(date=datetime.datetime(2015, 1, 1, 0, 0, 0, microsecond)).save()
        logs = list(LogEntry.objects.order_by("date"))
        for next_idx, log in enumerate(logs[:-1], start=1):
            next_log = logs[next_idx]
            assert log.date < next_log.date
        logs = list(LogEntry.objects.order_by("-date"))
        for next_idx, log in enumerate(logs[:-1], start=1):
            next_log = logs[next_idx]
            assert log.date > next_log.date
        logs = LogEntry.objects.filter(
            date__lte=datetime.datetime(2015, 1, 1, 0, 0, 0, 10000)
        )
        assert logs.count() == 4
    def test_no_default_value(self):
        class Log(Document):
            timestamp = ComplexDateTimeField()
        Log.drop_collection()
        log = Log()
        assert log.timestamp is None
        log.save()
        fetched_log = Log.objects.with_id(log.id)
        assert fetched_log.timestamp is None
    def test_default_static_value(self):
        NOW = datetime.datetime.utcnow()
        class Log(Document):
            timestamp = ComplexDateTimeField(default=NOW)
        Log.drop_collection()
        log = Log()
        assert log.timestamp == NOW
        log.save()
        fetched_log = Log.objects.with_id(log.id)
        assert fetched_log.timestamp == NOW
    def test_default_callable(self):
        NOW = datetime.datetime.utcnow()
        class Log(Document):
            timestamp = ComplexDateTimeField(default=datetime.datetime.utcnow)
        Log.drop_collection()
        log = Log()
        assert log.timestamp >= NOW
        log.save()
        fetched_log = Log.objects.with_id(log.id)
        assert fetched_log.timestamp >= NOW
    def test_setting_bad_value_does_not_raise_unless_validate_is_called(self):
        # test regression of #2253
        class Log(Document):
            timestamp = ComplexDateTimeField()
        Log.drop_collection()
        log = Log(timestamp="garbage")
        with pytest.raises(ValidationError):
            log.validate()
        with pytest.raises(ValidationError):
            log.save()
--- a/tests/fields/test_date_field.py
+++ b/tests/fields/test_date_field.py
@ -1,163 +0,0 @@
 import datetime
 import pytest
 try:
    import dateutil
 except ImportError:
    dateutil = None
 from mongoengine import *
 from tests.utils import MongoDBTestCase
 class TestDateField(MongoDBTestCase):
    def test_date_from_empty_string(self):
        """
        Ensure an exception is raised when trying to
        cast an empty string to datetime.
        """
        class MyDoc(Document):
            dt = DateField()
        md = MyDoc(dt="")
        with pytest.raises(ValidationError):
            md.save()
    def test_date_from_whitespace_string(self):
        """
        Ensure an exception is raised when trying to
        cast a whitespace-only string to datetime.
        """
        class MyDoc(Document):
            dt = DateField()
        md = MyDoc(dt="   ")
        with pytest.raises(ValidationError):
            md.save()
    def test_default_values_today(self):
        """Ensure that default field values are used when creating
        a document.
        """
        class Person(Document):
            day = DateField(default=datetime.date.today)
        person = Person()
        person.validate()
        assert person.day == person.day
        assert person.day == datetime.date.today()
        assert person._data["day"] == person.day
    def test_date(self):
        """Tests showing pymongo date fields
        See: http://api.mongodb.org/python/current/api/bson/son.html#dt
        """
        class LogEntry(Document):
            date = DateField()
        LogEntry.drop_collection()
        # Test can save dates
        log = LogEntry()
        log.date = datetime.date.today()
        log.save()
        log.reload()
        assert log.date == datetime.date.today()
        d1 = datetime.datetime(1970, 1, 1, 0, 0, 1, 999)
        d2 = datetime.datetime(1970, 1, 1, 0, 0, 1)
        log = LogEntry()
        log.date = d1
        log.save()
        log.reload()
        assert log.date == d1.date()
        assert log.date == d2.date()
        d1 = datetime.datetime(1970, 1, 1, 0, 0, 1, 9999)
        d2 = datetime.datetime(1970, 1, 1, 0, 0, 1, 9000)
        log.date = d1
        log.save()
        log.reload()
        assert log.date == d1.date()
        assert log.date == d2.date()
    def test_regular_usage(self):
        """Tests for regular datetime fields"""
        class LogEntry(Document):
            date = DateField()
        LogEntry.drop_collection()
        d1 = datetime.datetime(1970, 1, 1, 0, 0, 1)
        log = LogEntry()
        log.date = d1
        log.validate()
        log.save()
        for query in (d1, d1.isoformat(" ")):
            log1 = LogEntry.objects.get(date=query)
            assert log == log1
        if dateutil:
            log1 = LogEntry.objects.get(date=d1.isoformat("T"))
            assert log == log1
        # create additional 19 log entries for a total of 20
        for i in range(1971, 1990):
            d = datetime.datetime(i, 1, 1, 0, 0, 1)
            LogEntry(date=d).save()
        assert LogEntry.objects.count() == 20
        # Test ordering
        logs = LogEntry.objects.order_by("date")
        i = 0
        while i < 19:
            assert logs[i].date <= logs[i + 1].date
            i += 1
        logs = LogEntry.objects.order_by("-date")
        i = 0
        while i < 19:
            assert logs[i].date >= logs[i + 1].date
            i += 1
        # Test searching
        logs = LogEntry.objects.filter(date__gte=datetime.datetime(1980, 1, 1))
        assert logs.count() == 10
    def test_validation(self):
        """Ensure that invalid values cannot be assigned to datetime
        fields.
        """
        class LogEntry(Document):
            time = DateField()
        log = LogEntry()
        log.time = datetime.datetime.now()
        log.validate()
        log.time = datetime.date.today()
        log.validate()
        log.time = datetime.datetime.now().isoformat(" ")
        log.validate()
        if dateutil:
            log.time = datetime.datetime.now().isoformat("T")
            log.validate()
        log.time = -1
        with pytest.raises(ValidationError):
            log.validate()
        log.time = "ABC"
        with pytest.raises(ValidationError):
            log.validate()
--- a/tests/fields/test_datetime_field.py
+++ b/tests/fields/test_datetime_field.py
@ -1,232 +0,0 @@
 import datetime as dt
 import pytest
 try:
    import dateutil
 except ImportError:
    dateutil = None
 from mongoengine import *
 from mongoengine import connection
 from tests.utils import MongoDBTestCase
 class TestDateTimeField(MongoDBTestCase):
    def test_datetime_from_empty_string(self):
        """
        Ensure an exception is raised when trying to
        cast an empty string to datetime.
        """
        class MyDoc(Document):
            dt = DateTimeField()
        md = MyDoc(dt="")
        with pytest.raises(ValidationError):
            md.save()
    def test_datetime_from_whitespace_string(self):
        """
        Ensure an exception is raised when trying to
        cast a whitespace-only string to datetime.
        """
        class MyDoc(Document):
            dt = DateTimeField()
        md = MyDoc(dt="   ")
        with pytest.raises(ValidationError):
            md.save()
    def test_default_value_utcnow(self):
        """Ensure that default field values are used when creating
        a document.
        """
        class Person(Document):
            created = DateTimeField(default=dt.datetime.utcnow)
        utcnow = dt.datetime.utcnow()
        person = Person()
        person.validate()
        person_created_t0 = person.created
        assert person.created - utcnow < dt.timedelta(seconds=1)
        assert person_created_t0 == person.created  # make sure it does not change
        assert person._data["created"] == person.created
    def test_handling_microseconds(self):
        """Tests showing pymongo datetime fields handling of microseconds.
        Microseconds are rounded to the nearest millisecond and pre UTC
        handling is wonky.
        See: http://api.mongodb.org/python/current/api/bson/son.html#dt
        """
        class LogEntry(Document):
            date = DateTimeField()
        LogEntry.drop_collection()
        # Test can save dates
        log = LogEntry()
        log.date = dt.date.today()
        log.save()
        log.reload()
        assert log.date.date() == dt.date.today()
        # Post UTC - microseconds are rounded (down) nearest millisecond and
        # dropped
        d1 = dt.datetime(1970, 1, 1, 0, 0, 1, 999)
        d2 = dt.datetime(1970, 1, 1, 0, 0, 1)
        log = LogEntry()
        log.date = d1
        log.save()
        log.reload()
        assert log.date != d1
        assert log.date == d2
        # Post UTC - microseconds are rounded (down) nearest millisecond
        d1 = dt.datetime(1970, 1, 1, 0, 0, 1, 9999)
        d2 = dt.datetime(1970, 1, 1, 0, 0, 1, 9000)
        log.date = d1
        log.save()
        log.reload()
        assert log.date != d1
        assert log.date == d2
    def test_regular_usage(self):
        """Tests for regular datetime fields"""
        class LogEntry(Document):
            date = DateTimeField()
        LogEntry.drop_collection()
        d1 = dt.datetime(1970, 1, 1, 0, 0, 1)
        log = LogEntry()
        log.date = d1
        log.validate()
        log.save()
        for query in (d1, d1.isoformat(" ")):
            log1 = LogEntry.objects.get(date=query)
            assert log == log1
        if dateutil:
            log1 = LogEntry.objects.get(date=d1.isoformat("T"))
            assert log == log1
        # create additional 19 log entries for a total of 20
        for i in range(1971, 1990):
            d = dt.datetime(i, 1, 1, 0, 0, 1)
            LogEntry(date=d).save()
        assert LogEntry.objects.count() == 20
        # Test ordering
        logs = LogEntry.objects.order_by("date")
        i = 0
        while i < 19:
            assert logs[i].date <= logs[i + 1].date
            i += 1
        logs = LogEntry.objects.order_by("-date")
        i = 0
        while i < 19:
            assert logs[i].date >= logs[i + 1].date
            i += 1
        # Test searching
        logs = LogEntry.objects.filter(date__gte=dt.datetime(1980, 1, 1))
        assert logs.count() == 10
        logs = LogEntry.objects.filter(date__lte=dt.datetime(1980, 1, 1))
        assert logs.count() == 10
        logs = LogEntry.objects.filter(
            date__lte=dt.datetime(1980, 1, 1), date__gte=dt.datetime(1975, 1, 1)
        )
        assert logs.count() == 5
    def test_datetime_validation(self):
        """Ensure that invalid values cannot be assigned to datetime
        fields.
        """
        class LogEntry(Document):
            time = DateTimeField()
        log = LogEntry()
        log.time = dt.datetime.now()
        log.validate()
        log.time = dt.date.today()
        log.validate()
        log.time = dt.datetime.now().isoformat(" ")
        log.validate()
        log.time = "2019-05-16 21:42:57.897847"
        log.validate()
        if dateutil:
            log.time = dt.datetime.now().isoformat("T")
            log.validate()
        log.time = -1
        with pytest.raises(ValidationError):
            log.validate()
        log.time = "ABC"
        with pytest.raises(ValidationError):
            log.validate()
        log.time = "2019-05-16 21:GARBAGE:12"
        with pytest.raises(ValidationError):
            log.validate()
        log.time = "2019-05-16 21:42:57.GARBAGE"
        with pytest.raises(ValidationError):
            log.validate()
        log.time = "2019-05-16 21:42:57.123.456"
        with pytest.raises(ValidationError):
            log.validate()
    def test_parse_datetime_as_str(self):
        class DTDoc(Document):
            date = DateTimeField()
        date_str = "2019-03-02 22:26:01"
        # make sure that passing a parsable datetime works
        dtd = DTDoc()
        dtd.date = date_str
        assert isinstance(dtd.date, str)
        dtd.save()
        dtd.reload()
        assert isinstance(dtd.date, dt.datetime)
        assert str(dtd.date) == date_str
        dtd.date = "January 1st, 9999999999"
        with pytest.raises(ValidationError):
            dtd.validate()
 class TestDateTimeTzAware(MongoDBTestCase):
    def test_datetime_tz_aware_mark_as_changed(self):
        # Reset the connections
        connection._connection_settings = {}
        connection._connections = {}
        connection._dbs = {}
        connect(db="mongoenginetest", tz_aware=True)
        class LogEntry(Document):
            time = DateTimeField()
        LogEntry.drop_collection()
        LogEntry(time=dt.datetime(2013, 1, 1, 0, 0, 0)).save()
        log = LogEntry.objects.first()
        log.time = dt.datetime(2013, 1, 1, 0, 0, 0)
        assert ["time"] == log._changed_fields
--- a/Show More
+++ b/Show More