code: def render_message(self):
          
          message = None
          if self.title:
              message = '标题：{0}'.format(self.title)
          if self.message_time:
              message = '{0}\n时间：{1}'.format(message, self.time)
          if message:
              message = '{0}\n内容：{1}'.format(message, self.content)
          else:
              message = self.content
          return message
docs: 渲染消息
  
          :return: 渲染后的消息