global validation_queue_keep_running
if pipeline_queue_thread is not None:
validation_queue_keep_running = False
validation_queue.put(None)
pipeline_queue_thread.join()
After Change
if mv_constants.pipeline_queue_thread is not None:
mv_constants.validation_queue_keep_running = False
mv_constants.validation_queue.put(None)
mv_constants.pipeline_queue_thread.join()