code: def _add_extra_handlers(self, handlers):
          
          extra_handlers = [(h[0], h[1], {"microservice": self}) for h in self.extra_handlers]
          handlers.extend(extra_handlers)
docs: Adds the extra handler (defined by the user)
  
          :param handlers: a list of :py:class:`tornado.web.RequestHandler` instances.
          :return: