code: def ray_start_stop():
      subprocess.check_output(["ray", "start", "--head"])
      try:
          with set_env_var("RAY_ADDRESS", "http://127.0.0.1:8265"):
              yield
      finally:
          subprocess.check_output(["ray", "stop", "--force"])
  
imports: from contextlib import contextmanager
  import ray
  import json
  import os
  import logging
  import sys
  import subprocess
  from typing import Optional, Tuple
  import pytest
label_desc: Use image node_id 3 for calling a global function with example usage: ray_start_stop() without return types