Update connection.py

Author: efrederickson

mongoengine/connection.py

@@ -2,7 +2,10 @@
 
 from pymongo import MongoClient, ReadPreference, uri_parser
 from pymongo.common import _UUID_REPRESENTATIONS
-from pymongo.database_shared import _check_name
+try:
+    from pymongo.database_shared import _check_name
+except ImportError:
+    from pymongo.database import _check_name
 
 # DriverInfo was added in PyMongo 3.7.
 try: