code: def stop(self):
      if self._decref_thread:  # pragma: no branch
          self._queue.put_nowait((None, None, None))
          self._decref_thread.join(1)
  
imports: import asyncio
  import atexit
  import concurrent.futures
  import queue
  import threading
  from typing import List
  from weakref import WeakKeyDictionary, ref
  from ...lib.aio import get_isolation
  from ...typing import SessionType, TileableType
  from ..mode import enter_mode
label_desc: Use image node_id 4 for calling the DecrefRunner obj's underlying member method code with example usage: obj.stop() without return types