code: def listen(self):
          
  
          self.listening = True
          if self.threading:
              from threading import Thread
              self.listen_thread = Thread(target=self.listen_loop)
              self.listen_thread.daemon = True
              self.listen_thread.start()
  
              self.scheduler_thread = Thread(target=self.scheduler)
              self.scheduler_thread.daemon = True
              self.scheduler_thread.start()
  
          else:
              self.listen_loop()
docs: Starts the listen loop. If threading is enabled, then the loop will
          be started in its own thread.
  
          Args:
            None
  
          Returns:
            None