code: def _get_by_id_async(cls, id, parent=None, app=None, namespace=None,
                         **ctx_options):
      
      key = Key(cls._get_kind(), id, parent=parent, app=app, namespace=namespace)
      return key.get_async(**ctx_options)
docs: Returns an instance of Model class by ID (and app, namespace).
  
      This is the asynchronous version of Model._get_by_id().