code: def tell(self, message, sender=no_sender):
          
          if sender is not no_sender and not isinstance(sender, ActorRef):
              raise ValueError("Sender must be actor reference")
  
          self._cell.send_message(message, sender)
docs: Send a message to this actor. Asynchronous fire-and-forget.
  
          :param message: The message to send.
          :type message: Any
  
          :param sender: The sender of the message. If provided it will be made
              available to the receiving actor via the :attr:`Actor.sender` attribute.
          :type sender: :class:`Actor`