code: def _start_executor_manager_thread(self):
      if self._executor_manager_thread is None:
          # Start the processes so that their sentinels are known.
          if (
              not self._safe_to_dynamically_spawn_children
          ):  # ie, using fork.
              self._launch_processes()
          self._executor_manager_thread = _ExecutorManagerThread(self)
          self._executor_manager_thread.start()
          _threads_wakeups[
              self._executor_manager_thread
          ] = self._executor_manager_thread_wakeup
  
imports: import os
  from concurrent.futures import _base
  import queue
  import multiprocessing
  import multiprocessing.connection
  from multiprocessing.queues import Queue
  import threading
  import weakref
  from functools import partial
  import itertools
  import sys
  from traceback import format_exception
label_desc: Use image node_id 2 for calling the ProcessPoolExecutor obj's underlying member method code with example usage: obj._start_executor_manager_thread() without return types