code: def _enqueue(self, msg: Any, rid: int, signer: Signer) -> None:
          
          if rid not in self.outBoxes:
              self.outBoxes[rid] = deque()
          self.outBoxes[rid].append(msg)
docs: Enqueue the message into the remote's queue.
  
          :param msg: the message to enqueue
          :param rid: the id of the remote node