code: def shutdown(self, force=False):
          
          if not force:
              self.join()
  
          self._dbg(2, 'Shutting down queue...')
          self.workqueue.shutdown(True)
          self._dbg(2, 'Queue shut down.')
          self._del_status_bar()
docs: Stop executing any further jobs. If the force argument is True,
          the function does not wait until any queued jobs are completed but
          stops immediately.
  
          After emptying the queue it is restarted, so you may still call run()
          after using this method.
  
          :type  force: bool
          :param force: Whether to wait until all jobs were processed.