code: def reply(self, text, in_thread=None):
          
          if in_thread is None:
              in_thread = 'thread_ts' in self.body
  
          if in_thread:
              self.send(text, thread_ts=self.thread_ts)
          else:
              text = self.gen_reply(text)
              self.send(text)
docs: Send a reply to the sender using RTM API
  
              (This function doesn't supports formatted message
              when using a bot integration)
  
              If the message was send in a thread, answer in a thread per default.