code: def attach_http_service(cls, http_service: HTTPService):
          
          if cls._services['_http_service'] is None:
              cls._services['_http_service'] = http_service
              cls._set_bus(http_service)
          else:
              warnings.warn('HTTP service is already attached')
docs: Attaches a service for hosting
          :param http_service: A HTTPService instance