code: def join_finalize_worker():
      """join the worker close process"""
      global SAMPLER_POOL
      if SAMPLER_POOL is not None:
          SAMPLER_POOL.join()
      SAMPLER_POOL = None
  
imports: import atexit
  import gc
  import multiprocessing
  import os
  import queue
  import sys
  import time
  import traceback
  from enum import Enum
  from ..None import utils
  from ..base import dgl_warning, DGLError
  from .None import rpc
  from .constants import MAX_QUEUE_SIZE
  from .kvstore import close_kvstore, init_kvstore
  from .role import init_role
  from .rpc_client import connect_to_server
label_desc: Use image node_id 9 for calling a global function with example usage: join_finalize_worker() without return types