code: def find_records(self, collection_name, query={}, sort_by=None,
                       sort_direction=None, start=0, limit=None):
          cursor = self._get_collection(collection_name).find(query)
          if sort_by is not None:
              cursor = self._apply_sort(cursor, sort_by, sort_direction)
          cursor = cursor.skip(start)
          if limit is not None:
              cursor = cursor.limit(limit)
          return MongoDbCursor(cursor)