code: def start(self):
          
          if not self.started:
              self.started = True
              self.executor = ThreadPoolExecutor(max_workers=32)
              self.poller = self.executor.submit(self.poll_events)
          else:
              raise IllegalStateError("Dispatcher is already started.")
docs: Starts the event dispatcher.
  
          Initiates executor and start polling events.
  
          Raises:
              IllegalStateError: Can't start a dispatcher again when it's already
                  running.