code: def api_class(self, resource_name=None, path=None, audiences=None,
                  scopes=None, allowed_client_ids=None, auth_level=None,
                  api_key_required=None):
      if auth_level is not None:
        _logger.warn(_AUTH_LEVEL_WARNING)
      def apiserving_api_decorator(api_class):
        self.__classes.append(api_class)
        api_class.api_info = _ApiInfo(
            self.__common_info, resource_name=resource_name,
            path=path, audiences=audiences, scopes=scopes,
            allowed_client_ids=allowed_client_ids, auth_level=auth_level,
            api_key_required=api_key_required)
        return api_class
      return apiserving_api_decorator