Added some imports for PyMongo 1.9 compatibility.

mongoengine/base.py

@@ -3,6 +3,7 @@ from queryset import DoesNotExist, MultipleObjectsReturned
 
 import sys
 import pymongo
+import pymongo.objectid
 
 
 _document_registry = {}

mongoengine/fields.py

@@ -5,6 +5,9 @@ from operator import itemgetter
 
 import re
 import pymongo
+import pymongo.dbref
+import pymongo.son
+import pymongo.binary
 import datetime
 import decimal
 

mongoengine/queryset.py

@@ -1,6 +1,9 @@
 from connection import _get_db
 
 import pymongo
+import pymongo.code
+import pymongo.dbref
+import pymongo.objectid
 import re
 import copy