code: def _async_executor(pool):
      with _async_executor_lock:
          executor = _async_executor_cache.get(pool)
          if executor is None:
              max_workers = _async_get_max_workers(pool)
              executor = _futures.ThreadPoolExecutor(max_workers)
              _async_executor_cache[pool] = executor
      return executor
  
imports: from os import cpu_count
  import functools
  import operator
  import threading
  import warnings
  import weakref
  from ..None import futures
label_desc: Use image node_id 4 for calling a global function with example usage: _async_executor(pool) and returns: executor