diff --git a/.gitignore b/.gitignore
index e191be82..95ad521c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 *.pyc
 .*.swp
 docs/.build
+docs/_build
diff --git a/docs/Makefile b/docs/Makefile
index 66cd648f..76eb910c 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -5,7 +5,7 @@
 SPHINXOPTS    =
 SPHINXBUILD   = sphinx-build
 PAPER         =
-BUILDDIR      = .build
+BUILDDIR      = _build
 
 # Internal variables.
 PAPEROPT_a4     = -D latex_paper_size=a4
diff --git a/docs/.themes/nature/static/nature.css_t b/docs/_themes/nature/static/nature.css_t
similarity index 100%
rename from docs/.themes/nature/static/nature.css_t
rename to docs/_themes/nature/static/nature.css_t
diff --git a/docs/.themes/nature/static/pygments.css b/docs/_themes/nature/static/pygments.css
similarity index 100%
rename from docs/.themes/nature/static/pygments.css
rename to docs/_themes/nature/static/pygments.css
diff --git a/docs/.themes/nature/theme.conf b/docs/_themes/nature/theme.conf
similarity index 100%
rename from docs/.themes/nature/theme.conf
rename to docs/_themes/nature/theme.conf
diff --git a/docs/apireference.rst b/docs/apireference.rst
new file mode 100644
index 00000000..9ec4321a
--- /dev/null
+++ b/docs/apireference.rst
@@ -0,0 +1,46 @@
+API Reference
+=============
+
+Connecting
+----------
+
+.. autofunction:: mongoengine.connect
+
+Documents
+---------
+
+.. autoclass:: mongoengine.Document
+   :members:
+
+   .. attribute:: objects
+
+      A :class:`~mongoengine.queryset.QuerySet` object that is created lazily 
+      on access.
+
+.. autoclass:: mongoengine.EmbeddedDocument
+   :members:
+
+Querying
+--------
+
+.. autoclass:: mongoengine.queryset.QuerySet
+   :members:
+
+Fields
+------
+
+.. autoclass:: mongoengine.StringField
+
+.. autoclass:: mongoengine.IntField
+
+.. autoclass:: mongoengine.FloatField
+
+.. autoclass:: mongoengine.DateTimeField
+
+.. autoclass:: mongoengine.EmbeddedDocumentField
+
+.. autoclass:: mongoengine.ListField
+
+.. autoclass:: mongoengine.ObjectIdField
+
+.. autoclass:: mongoengine.ReferenceField
diff --git a/docs/conf.py b/docs/conf.py
index 5b29b371..be7d3f5d 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -16,13 +16,13 @@ import sys, os
 # 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.append(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 = []
+extensions = ['sphinx.ext.autodoc']
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['.templates']
@@ -64,7 +64,7 @@ release = '0.1'
 
 # 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
@@ -99,7 +99,7 @@ html_theme = 'nature'
 #html_theme_options = {}
 
 # Add any paths that contain custom themes here, relative to this directory.
-html_theme_path = ['.themes']
+html_theme_path = ['_themes']
 
 # The name for this set of Sphinx documents.  If None, it defaults to
 # "<project> v<release> documentation".
@@ -120,7 +120,7 @@ html_theme_path = ['.themes']
 # 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.
diff --git a/docs/index.rst b/docs/index.rst
index 5fab07a6..e6a2bde6 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -3,7 +3,7 @@
    You can adapt this file completely to your liking, but it should at least
    contain the root `toctree` directive.
 
-Welcome to MongoEngine's documentation!
+MongoEngine User Documentation
 =======================================
 
 Contents:
@@ -12,6 +12,7 @@ Contents:
    :maxdepth: 2
 
    tutorial.rst
+   apireference.rst
 
 Indices and tables
 ==================
diff --git a/mongoengine/base.py b/mongoengine/base.py
index 6cb453c1..e098116b 100644
--- a/mongoengine/base.py
+++ b/mongoengine/base.py
@@ -136,20 +136,36 @@ class TopLevelDocumentMetaclass(DocumentMetaclass):
         if attrs.get('__metaclass__') == TopLevelDocumentMetaclass:
             return super_new(cls, name, bases, attrs)
 
-        collection = attrs.get('__collection__', name.lower())
+        collection = name.lower()
         
+        simple_class = True
+
         # Subclassed documents inherit collection from superclass
         for base in bases:
             if hasattr(base, '_meta') and 'collection' in base._meta:
+                # Ensure that the Document class may be subclassed - 
+                # inheritance may be disabled to remove dependency on 
+                # additional fields _cls and _types
+                if base._meta.get('allow_inheritance', True) == False:
+                    raise ValueError('Document %s may not be subclassed' %
+                                     base.__name__)
+                else:
+                    simple_class = False
                 collection = base._meta['collection']
 
         meta = {
             'collection': collection,
+            'allow_inheritance': True,
         }
         meta.update(attrs.get('meta', {}))
+        # Only simple classes - direct subclasses of Document - may set
+        # allow_inheritance to False
+        if not simple_class and not meta['allow_inheritance']:
+            raise ValueError('Only direct subclasses of Document may set '
+                             '"allow_inheritance" to False')
         attrs['_meta'] = meta
 
-        attrs['_id'] = ObjectIdField()
+        attrs['id'] = ObjectIdField(name='_id')
 
         # Set up collection manager, needs the class to have fields so use
         # DocumentMetaclass before instantiating CollectionManager object
@@ -168,10 +184,11 @@ class BaseDocument(object):
             if attr_name in values:
                 setattr(self, attr_name, values.pop(attr_name))
             else:
-                if attr_value.required:
+                # Use default value if present
+                value = getattr(self, attr_name, None)
+                if value is None and attr_value.required:
                     raise ValidationError('Field "%s" is required' % attr_name)
-                # Use default value
-                setattr(self, attr_name, getattr(self, attr_name, None))
+                setattr(self, attr_name, value)
 
     @classmethod
     def _get_subclasses(cls):
@@ -226,9 +243,12 @@ class BaseDocument(object):
         for field_name, field in self._fields.items():
             value = getattr(self, field_name, None)
             if value is not None:
-                data[field_name] = field.to_mongo(value)
-        data['_cls'] = self._class_name
-        data['_types'] = self._superclasses.keys() + [self._class_name]
+                data[field.name] = field.to_mongo(value)
+        # Only add _cls and _types if allow_inheritance is not False
+        if not (hasattr(self, '_meta') and
+                self._meta.get('allow_inheritance', True) == False):
+            data['_cls'] = self._class_name
+            data['_types'] = self._superclasses.keys() + [self._class_name]
         return data
     
     @classmethod
@@ -241,6 +261,9 @@ class BaseDocument(object):
 
         data = dict((str(key), value) for key, value in son.items())
 
+        if '_types' in data:
+            del data['_types']
+
         if '_cls' in data:
             del data['_cls']
 
@@ -254,7 +277,7 @@ class BaseDocument(object):
             cls = subclasses[class_name]
 
         for field_name, field in cls._fields.items():
-            if field_name in data:
-                data[field_name] = field.to_python(data[field_name])
+            if field.name in data:
+                data[field_name] = field.to_python(data[field.name])
 
         return cls(**data)
diff --git a/mongoengine/document.py b/mongoengine/document.py
index 359a1789..a4b78619 100644
--- a/mongoengine/document.py
+++ b/mongoengine/document.py
@@ -6,25 +6,58 @@ __all__ = ['Document', 'EmbeddedDocument']
 
 
 class EmbeddedDocument(BaseDocument):
+    """A :class:`~mongoengine.Document` that isn't stored in its own
+    collection.  :class:`~mongoengine.EmbeddedDocument`\ s should be used as
+    fields on :class:`~mongoengine.Document`\ s through the
+    :class:`~mongoengine.EmbeddedDocumentField` field type.
+    """
     
     __metaclass__ = DocumentMetaclass
 
 
 class Document(BaseDocument):
+    """The base class used for defining the structure and properties of
+    collections of documents stored in MongoDB. Inherit from this class, and
+    add fields as class attributes to define a document's structure.
+    Individual documents may then be created by making instances of the
+    :class:`~mongoengine.Document` subclass.
+
+    By default, the MongoDB collection used to store documents created using a
+    :class:`~mongoengine.Document` subclass will be the name of the subclass
+    converted to lowercase. A different collection may be specified by
+    providing :attr:`collection` to the :attr:`meta` dictionary in the class
+    definition.
+
+    A :class:`~mongoengine.Document` subclass may be itself subclassed, to
+    create a specialised version of the document that will be stored in the
+    same collection. To facilitate this behaviour, `_cls` and `_types`
+    fields are added to documents (hidden though the MongoEngine interface
+    though). To disable this behaviour and remove the dependence on the
+    presence of `_cls` and `_types`, set :attr:`allow_inheritance` to
+    ``False`` in the :attr:`meta` dictionary.
+    """
 
     __metaclass__ = TopLevelDocumentMetaclass
 
     def save(self):
-        """Save the document to the database. If the document already exists,
-        it will be updated, otherwise it will be created.
+        """Save the :class:`~mongoengine.Document` to the database. If the
+        document already exists, it will be updated, otherwise it will be
+        created.
         """
-        _id = self.objects._collection.save(self.to_mongo())
-        self._id = _id
+        object_id = self.objects._collection.save(self.to_mongo())
+        self.id = object_id
+
+    def delete(self):
+        """Delete the :class:`~mongoengine.Document` from the database. This
+        will only take effect if the document has been previously saved.
+        """
+        object_id = self._fields['id'].to_mongo(self.id)
+        self.__class__.objects(_id=object_id).delete()
 
     @classmethod
     def drop_collection(cls):
-        """Drops the entire collection associated with this Document type from
-        the database.
+        """Drops the entire collection associated with this
+        :class:`~mongoengine.Document` type from the database.
         """
         db = _get_db()
         db.drop_collection(cls._meta['collection'])
diff --git a/mongoengine/fields.py b/mongoengine/fields.py
index c8a9086d..e97aadb2 100644
--- a/mongoengine/fields.py
+++ b/mongoengine/fields.py
@@ -87,7 +87,7 @@ class DateTimeField(BaseField):
 
 class EmbeddedDocumentField(BaseField):
     """An embedded document field. Only valid values are subclasses of 
-    EmbeddedDocument. 
+    :class:`~mongoengine.EmbeddedDocument`. 
     """
 
     def __init__(self, document, **kwargs):
@@ -179,19 +179,19 @@ class ReferenceField(BaseField):
 
     def to_mongo(self, document):
         if isinstance(document, (str, unicode, pymongo.objectid.ObjectId)):
-            _id = document
+            id_ = document
         else:
             try:
-                _id = document._id
+                id_ = document.id
             except:
                 raise ValidationError('You can only reference documents once '
                                       'they have been saved to the database')
 
-        if not isinstance(_id, pymongo.objectid.ObjectId):
-            _id = pymongo.objectid.ObjectId(_id)
+        if not isinstance(id_, pymongo.objectid.ObjectId):
+            id_ = pymongo.objectid.ObjectId(id_)
 
         collection = self.document_type._meta['collection']
-        return pymongo.dbref.DBRef(collection, _id)
+        return pymongo.dbref.DBRef(collection, id_)
 
     def validate(self, value):
         assert(isinstance(value, (self.document_type, pymongo.dbref.DBRef)))
diff --git a/mongoengine/queryset.py b/mongoengine/queryset.py
index dd860524..e324c529 100644
--- a/mongoengine/queryset.py
+++ b/mongoengine/queryset.py
@@ -5,15 +5,19 @@ import pymongo
 
 class QuerySet(object):
     """A set of results returned from a query. Wraps a MongoDB cursor, 
-    providing Document objects as the results.
+    providing :class:`~mongoengine.Document` objects as the results.
     """
     
     def __init__(self, document, collection):
         self._document = document
         self._collection = collection
         self._query = {}
+
+        # If inheritance is allowed, only return instances and instances of
+        # subclasses of the class being used
+        if document._meta.get('allow_inheritance'):
+            self._query = {'_types': self._document._class_name}
         self._cursor_obj = None
-        self._ordering = []
         
     def ensure_index(self, key_or_list, direction=None):
         """Ensure that the given indexes are in place.
@@ -29,7 +33,8 @@ class QuerySet(object):
         return self
 
     def __call__(self, **query):
-        """Filter the selected documents by calling the queryset with a query.
+        """Filter the selected documents by calling the 
+        :class:`~mongoengine.QuerySet` with a query.
         """
         self._query.update(QuerySet._transform_query(**query))
         return self
@@ -73,7 +78,7 @@ class QuerySet(object):
         return result
 
     def with_id(self, object_id):
-        """Retrieve the object matching the _id provided.
+        """Retrieve the object matching the id provided.
         """
         if not isinstance(object_id, pymongo.objectid.ObjectId):
             object_id = pymongo.objectid.ObjectId(object_id)
@@ -84,7 +89,7 @@ class QuerySet(object):
         return result
 
     def next(self):
-        """Wrap the result in a Document object.
+        """Wrap the result in a :class:`~mongoengine.Document` object.
         """
         return self._document._from_son(self._cursor.next())
 
@@ -94,41 +99,54 @@ class QuerySet(object):
         return self._cursor.count()
 
     def limit(self, n):
-        """Limit the number of returned documents to.
+        """Limit the number of returned documents to `n`. This may also be
+        achieved using array-slicing syntax (e.g. ``User.objects[:5]``).
         """
         self._cursor.limit(n)
         # Return self to allow chaining
         return self
 
     def skip(self, n):
-        """Skip n documents before returning the results.
+        """Skip `n` documents before returning the results. This may also be
+        achieved using array-slicing syntax (e.g. ``User.objects[5:]``).
         """
         self._cursor.skip(n)
         return self
-        
-    def order_by(self, *params):
-        """Apply ordering conditions, Django-style.
-        
-        e.g., ``Model.objects.().order_by("-published_date", "ordering")``
-        will order first by ``published_date DESC``, and then ``ordering ASC``.
-        
-        """
-        if not params:
-            self._ordering = []
-        for param in params:
-            if param.startswith("-"):
-                param = param[1:]
-                sort_dir = pymongo.DESCENDING
-            else:
-                sort_dir = pymongo.ASCENDING
-            sort_rule = (param, sort_dir)
 
-            if not sort_rule in self._ordering:
-                self._ordering.append(sort_rule)
-        self._cursor.sort(self._ordering)
+    def __getitem__(self, key):
+        """Support skip and limit using getitem and slicing syntax.
+        """
+        # Slice provided
+        if isinstance(key, slice):
+            self._cursor_obj = self._cursor[key]
+            # Allow further QuerySet modifications to be performed
+            return self
+        # Integer index provided
+        elif isinstance(key, int):
+            return self._document._from_son(self._cursor[key])
+
+    def order_by(self, *keys):
+        """Order the :class:`~mongoengine.queryset.QuerySet` by the keys. The
+        order may be specified by prepending each of the keys by a + or a -.
+        Ascending order is assumed.
+        """
+        key_list = []
+        for key in keys:
+            direction = pymongo.ASCENDING
+            if key[0] == '-':
+                direction = pymongo.DESCENDING
+            if key[0] in ('-', '+'):
+                key = key[1:]
+            key_list.append((key, direction)) 
+
+        self._cursor.sort(key_list)
         return self
         
     def explain(self, format=False):
+        """Return an explain plan record for the 
+        :class:`~mongoengine.queryset.QuerySet`\ 's cursor.
+        """
+
         plan = self._cursor.explain()
         if format:
             import pprint
diff --git a/tests/document.py b/tests/document.py
index c20e9b33..bec66ee9 100644
--- a/tests/document.py
+++ b/tests/document.py
@@ -41,7 +41,7 @@ class DocumentTest(unittest.TestCase):
         self.assertEqual(Person._fields['name'], name_field)
         self.assertEqual(Person._fields['age'], age_field)
         self.assertFalse('non_field' in Person._fields)
-        self.assertTrue('_id' in Person._fields)
+        self.assertTrue('id' in Person._fields)
         # Test iteration over fields
         fields = list(Person())
         self.assertTrue('name' in fields and 'age' in fields)
@@ -126,6 +126,36 @@ class DocumentTest(unittest.TestCase):
         self.assertEqual(Employee._meta['collection'], 
                          self.Person._meta['collection'])
 
+    def test_allow_inheritance(self):
+        """Ensure that inheritance may be disabled on simple classes and that
+        _cls and _types will not be used.
+        """
+        class Animal(Document):
+            meta = {'allow_inheritance': False}
+            name = StringField()
+
+        Animal.drop_collection()
+
+        def create_dog_class():
+            class Dog(Animal):
+                pass
+        self.assertRaises(ValueError, create_dog_class)
+        
+        # Check that _cls etc aren't present on simple documents
+        dog = Animal(name='dog')
+        dog.save()
+        collection = self.db[Animal._meta['collection']]
+        obj = collection.find_one()
+        self.assertFalse('_cls' in obj)
+        self.assertFalse('_types' in obj)
+
+        Animal.drop_collection()
+
+        def create_employee_class():
+            class Employee(self.Person):
+                meta = {'allow_inheritance': False}
+        self.assertRaises(ValueError, create_employee_class)
+
     def test_creation(self):
         """Ensure that document may be created using keyword arguments.
         """
@@ -145,7 +175,7 @@ class DocumentTest(unittest.TestCase):
         person['name'] = 'Another User'
         self.assertEquals(person['name'], 'Another User')
 
-        # Length = length(assigned fields + _id)
+        # Length = length(assigned fields + id)
         self.assertEquals(len(person), 3)
 
         self.assertTrue('age' in person)
@@ -160,7 +190,7 @@ class DocumentTest(unittest.TestCase):
             content = StringField()
         
         self.assertTrue('content' in Comment._fields)
-        self.assertFalse('_id' in Comment._fields)
+        self.assertFalse('id' in Comment._fields)
         self.assertFalse(hasattr(Comment, '_meta'))
 
     def test_save(self):
@@ -174,14 +204,23 @@ class DocumentTest(unittest.TestCase):
         person_obj = collection.find_one({'name': 'Test User'})
         self.assertEqual(person_obj['name'], 'Test User')
         self.assertEqual(person_obj['age'], 30)
-        self.assertEqual(person_obj['_id'], person._id)
+        self.assertEqual(person_obj['_id'], person.id)
+
+    def test_delete(self):
+        """Ensure that document may be deleted using the delete method.
+        """
+        person = self.Person(name="Test User", age=30)
+        person.save()
+        self.assertEqual(self.Person.objects.count(), 1)
+        person.delete()
+        self.assertEqual(self.Person.objects.count(), 0)
 
     def test_save_custom_id(self):
         """Ensure that a document may be saved with a custom _id.
         """
         # Create person object and save it to the database
         person = self.Person(name='Test User', age=30, 
-                             _id='497ce96f395f2f052a494fd4')
+                             id='497ce96f395f2f052a494fd4')
         person.save()
         # Ensure that the object is in the database with the correct _id
         collection = self.db[self.Person._meta['collection']]
@@ -268,7 +307,7 @@ class DocumentTest(unittest.TestCase):
         post_obj.author.age = 25
         post_obj.author.save()
 
-        author = self.Person.objects(name='Test User').first()
+        author = list(self.Person.objects(name='Test User'))[-1]
         self.assertEqual(author.age, 25)
 
         BlogPost.drop_collection()
diff --git a/tests/fields.py b/tests/fields.py
index e8e7a46b..49c3f70f 100644
--- a/tests/fields.py
+++ b/tests/fields.py
@@ -46,10 +46,10 @@ class FieldTest(unittest.TestCase):
             name = StringField()
         
         person = Person(name='Test User')
-        self.assertRaises(AttributeError, getattr, person, '_id')
-        self.assertRaises(ValidationError, person.__setattr__, '_id', 47)
-        self.assertRaises(ValidationError, person.__setattr__, '_id', 'abc')
-        person._id = '497ce96f395f2f052a494fd4'
+        self.assertRaises(AttributeError, getattr, person, 'id')
+        self.assertRaises(ValidationError, person.__setattr__, 'id', 47)
+        self.assertRaises(ValidationError, person.__setattr__, 'id', 'abc')
+        person.id = '497ce96f395f2f052a494fd4'
 
     def test_string_validation(self):
         """Ensure that invalid values cannot be assigned to string fields.
diff --git a/tests/queryset.py b/tests/queryset.py
index 344ee65d..b73bab17 100644
--- a/tests/queryset.py
+++ b/tests/queryset.py
@@ -53,7 +53,7 @@ class QuerySetTest(unittest.TestCase):
         self.assertEqual(people.count(), 2)
         results = list(people)
         self.assertTrue(isinstance(results[0], self.Person))
-        self.assertTrue(isinstance(results[0]._id, (pymongo.objectid.ObjectId,
+        self.assertTrue(isinstance(results[0].id, (pymongo.objectid.ObjectId,
                                                     str, unicode)))
         self.assertEqual(results[0].name, "User A")
         self.assertEqual(results[0].age, 20)
@@ -77,6 +77,26 @@ class QuerySetTest(unittest.TestCase):
         self.assertEqual(len(people), 1)
         self.assertEqual(people[0].name, 'User B')
 
+        person3 = self.Person(name="User C", age=40)
+        person3.save()
+
+        # Test slice limit
+        people = list(self.Person.objects[:2])
+        self.assertEqual(len(people), 2)
+        self.assertEqual(people[0].name, 'User A')
+        self.assertEqual(people[1].name, 'User B')
+
+        # Test slice skip
+        people = list(self.Person.objects[1:])
+        self.assertEqual(len(people), 2)
+        self.assertEqual(people[0].name, 'User B')
+        self.assertEqual(people[1].name, 'User C')
+
+        # Test slice limit and skip
+        people = list(self.Person.objects[1:2])
+        self.assertEqual(len(people), 1)
+        self.assertEqual(people[0].name, 'User B')
+
     def test_find_one(self):
         """Ensure that a query using find_one returns a valid result.
         """
@@ -97,9 +117,18 @@ class QuerySetTest(unittest.TestCase):
 
         person = self.Person.objects(age__lt=30).first()
         self.assertEqual(person.name, "User A")
+
+        # Use array syntax
+        person = self.Person.objects[0]
+        self.assertEqual(person.name, "User A")
+
+        person = self.Person.objects[1]
+        self.assertEqual(person.name, "User B")
+
+        self.assertRaises(IndexError, self.Person.objects.__getitem__, 2)
         
         # Find a document using just the object id
-        person = self.Person.objects.with_id(person1._id)
+        person = self.Person.objects.with_id(person1.id)
         self.assertEqual(person.name, "User A")
 
     def test_find_embedded(self):
@@ -137,6 +166,25 @@ class QuerySetTest(unittest.TestCase):
         self.Person.objects.delete()
         self.assertEqual(self.Person.objects.count(), 0)
 
+    def test_order_by(self):
+        """Ensure that QuerySets may be ordered.
+        """
+        self.Person(name="User A", age=20).save()
+        self.Person(name="User B", age=40).save()
+        self.Person(name="User C", age=30).save()
+
+        names = [p.name for p in self.Person.objects.order_by('-age')]
+        self.assertEqual(names, ['User B', 'User C', 'User A'])
+
+        names = [p.name for p in self.Person.objects.order_by('+age')]
+        self.assertEqual(names, ['User A', 'User C', 'User B'])
+
+        names = [p.name for p in self.Person.objects.order_by('age')]
+        self.assertEqual(names, ['User A', 'User C', 'User B'])
+        
+        ages = [p.age for p in self.Person.objects.order_by('-name')]
+        self.assertEqual(ages, [30, 40, 20])
+
     def tearDown(self):
         self.Person.drop_collection()