code: def stop(self, timeout=None, force=False):
          
  
          self.signal_stop()
          self.wait_stopped(timeout, force)
docs: Stop the worker thread and synchronously wait for it to finish.
  
          Args:
              timeout (float): The maximum time to wait for the thread to stop
                  before raising a TimeoutExpiredError.  If force is True, TimeoutExpiredError
                  is not raised and the thread is just marked as a daemon thread
                  so that it does not block cleanly exiting the process.
              force (bool): If true and the thread does not exit in timeout seconds
                  no error is raised since the thread is marked as daemon and will
                  be killed when the process exits.