improve 2-3 codebase compatibility

mongoengine/base/common.py

@@ -3,10 +3,10 @@ from mongoengine.errors import NotRegistered
 __all__ = ('UPDATE_OPERATORS', 'get_document', '_document_registry')
 
 
-UPDATE_OPERATORS = set(['set', 'unset', 'inc', 'dec', 'mul',
-                        'pop', 'push', 'push_all', 'pull',
-                        'pull_all', 'add_to_set', 'set_on_insert',
-                        'min', 'max', 'rename'])
+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 = {}

mongoengine/base/datastructures.py

@@ -377,7 +377,7 @@ class EmbeddedDocumentList(BaseList):
 
 class StrictDict(object):
     __slots__ = ()
-    _special_fields = set(['get', 'pop', 'iteritems', 'items', 'keys', 'create'])
+    _special_fields = {'get', 'pop', 'iteritems', 'items', 'keys', 'create'}
     _classes = {}
 
     def __init__(self, **kwargs):

mongoengine/base/document.py

@@ -302,7 +302,7 @@ class BaseDocument(object):
         data['_cls'] = self._class_name
 
         # only root fields ['test1.a', 'test2'] => ['test1', 'test2']
-        root_fields = set([f.split('.')[0] for f in fields])
+        root_fields = {f.split('.')[0] for f in fields}
 
         for field_name in self:
             if root_fields and field_name not in root_fields:
@@ -567,7 +567,7 @@ class BaseDocument(object):
                     continue
                 elif isinstance(field, SortedListField) and field._ordering:
                     # if ordering is affected whole list is changed
-                    if any(map(lambda d: field._ordering in d._changed_fields, data)):
+                    if any(field._ordering in d._changed_fields for d in data):
                         changed_fields.append(db_field_name)
                         continue
 

mongoengine/base/fields.py

@@ -501,7 +501,7 @@ class GeoJsonBaseField(BaseField):
     def validate(self, value):
         """Validate the GeoJson object based on its type."""
         if isinstance(value, dict):
-            if set(value.keys()) == set(['type', 'coordinates']):
+            if set(value.keys()) == {'type', 'coordinates'}:
                 if value['type'] != self._type:
                     self.error('%s type must be "%s"' %
                                (self._name, self._type))