code: def _ProcessMessageHandlerRequests(self, requests):
      
      logging.debug("Leased message handler request ids: %s",
                    ",".join(str(r.request_id) for r in requests))
      grouped_requests = collection.Group(requests, lambda r: r.handler_name)
      for handler_name, requests_for_handler in iteritems(grouped_requests):
        handler_cls = handler_registry.handler_name_map.get(handler_name)
        if not handler_cls:
          logging.error("Unknown message handler: %s", handler_name)
          continue
  
        stats_collector_instance.Get().IncrementCounter(
            "well_known_flow_requests", fields=[handler_name])
  
        try:
          logging.debug("Running %d messages for handler %s",
                        len(requests_for_handler), handler_name)
          handler_cls(token=self.token).ProcessMessages(requests_for_handler)
        except Exception as e:  # pylint: disable=broad-except
          logging.exception("Exception while processing message handler %s: %s",
                            handler_name, e)
  
      logging.debug("Deleting message handler request ids: %s",
                    ",".join(str(r.request_id) for r in requests))
      data_store.REL_DB.DeleteMessageHandlerRequests(requests)
docs: Processes message handler requests.