docs: def send(self, message):
          """Sends a RTMMessage
          Should be called after starting the loop
  
          Args:
              message(RTMMessage): the sending message
  
          Raises:
              WebSocketConnectionClosedException: if the loop is closed
          """
          if "call_id" not in message:
              message["call_id"] = self.gen_call_id()
  
          self._ws.send(message.to_json())