code: def make_datastore_query(self, cursor=None):
      
      filters = {}
      filters['__key__ >= '] = _key_for_namespace(
          self.namespace_start, self.app)
      filters['__key__ <= '] = _key_for_namespace(
          self.namespace_end, self.app)
  
      return datastore.Query('__namespace__',
                             filters=filters,
                             keys_only=True,
                             cursor=cursor,
                             _app=self.app)
docs: Returns a datastore.Query that generates all namespaces in the range.
  
      Args:
        cursor: start cursor for the query.
  
      Returns:
        A datastore.Query instance that generates db.Keys for each namespace in
        the NamespaceRange.