code: def _hook(env):
      return {"env_vars": {"HOOK_KEY": "HOOK_VALUE"}}
  
imports: import os
  import re
  import signal
  import subprocess
  import sys
  import time
  import pytest
  import ray
  from ray._private.test_utils import run_string_as_driver, run_string_as_driver_nonblocking, wait_for_condition
label_desc: Use image node_id 5 for calling a global function with example usage: _hook(env) and returns: dict