code: def test_initializer(shutdown_only):
      def init(dirname):
          with open(os.path.join(dirname, str(os.getpid())), "w") as f:
              print("hello", file=f)
  
      with tempfile.TemporaryDirectory() as dirname:
          num_processes = 4
          pool = Pool(
              processes=num_processes,
              initializer=init,
              initargs=(dirname,),
          )
  
          assert len(os.listdir(dirname)) == 4
          pool.terminate()
          pool.join()
  
imports: import os
  import sys
  import platform
  import pytest
  import tempfile
  import time
  import random
  from collections import defaultdict
  import queue
  import math
  import ray
  from ray._private.test_utils import SignalActor
  from ray.util.multiprocessing import Pool, TimeoutError, JoinableQueue
  from ray.util.joblib import register_ray
  from joblib import parallel_backend, Parallel, delayed
label_desc: Use image node_id 9 for calling a global function with example usage: test_initializer(shutdown_only) without return types