code: def _convert_appengine_app_assertion_credentials(credentials):
      
      # pylint: disable=invalid-name
      return google.auth.app_engine.Credentials(
          scopes=_helpers.string_to_scopes(credentials.scope),
          service_account_id=credentials.service_account_id)
docs: Converts to :class:`google.auth.app_engine.Credentials`.
  
      Args:
          credentials (oauth2client.contrib.app_engine.AppAssertionCredentials):
              The credentials to convert.
  
      Returns:
          google.oauth2.service_account.Credentials: The converted credentials.