code: def _recv_nack(self, method_frame):
          '''Receive a nack from the broker.'''
          if self._nack_listener:
              delivery_tag = method_frame.args.read_longlong()
              multiple, requeue = method_frame.args.read_bits(2)
              if multiple:
                  while self._last_ack_id < delivery_tag:
                      self._last_ack_id += 1
                      self._nack_listener(self._last_ack_id, requeue)
              else:
                  self._last_ack_id = delivery_tag
                  self._nack_listener(self._last_ack_id, requeuef _recv_nack(self, method_frame):
          '''Receive a nack from the broker.'''
          if self._nack_listener:
              delivery_tag = method_frame.args.read_longlong()
              multiple, requeue = method_frame.args.read_bits(2)
              if multiple:
                  while self._last_ack_id < delivery_tag:
                      self._last_ack_id += 1
                      self._nack_listener(self._last_ack_id, requeue)
              else:
                  self._last_ack_id = delivery_tag
                  self._nack_listener(self._last_ack_id, requeue)
docs: Receive a nack from the broker.