code: def setUp(self):
      self._threading_key = threading_helper.threading_setup()
      self.alive = {}
      self.stop = 0
      self.threads = []
  
file_path: cpython/Lib/test/fork_wait.py
imports: import os, time, unittest
  import threading
  from test import support
  from test.support import threading_helper
  import warnings
label_desc: Use image node_id 1 for calling the ForkWait obj's underlying member method code with example usage: obj.setUp() without return types