code: def requeue(self, message_id, timeout=0, backoff=True):
          
          self.send(nsq.requeue(message_id, timeout))
          self.finish_inflight()
          self.on_requeue.send(
              self,
              message_id=message_id,
              timeout=timeout,
              backoff=backoff
          )
docs: Re-queue a message (indicate failure to process).