code: def add(self, message):
          
          if self._is_stringable(message) or self._is_qstring(message):
              self.message.append(Text(message))
          elif isinstance(message, MessageElement):
              self.message.append(message)
          elif isinstance(message, Message):
              self.message.extend(message.message)
          else:
              raise InvalidMessageItemError(message, message.__class__)
docs: Add a MessageElement to the end of the queue.
  
          Strings can be passed and are automatically converted in to
          item.Text()
  
          :param message: An element to add to the message queue.
          :type message: safe.messaging.Message, MessageElement, str