code: def _actor_killed(pid: str) -> bool:
      """Check For the existence of a unix pid."""
      try:
          os.kill(pid, 0)
      except OSError:
          return True
      else:
          return False
  
file_path: ray/dashboard/modules/snapshot/tests/test_actors.py
imports: import logging
  import os
  import sys
  import time
  import pytest
  import requests
  import ray
  from ray._private.test_utils import format_web_url, wait_until_server_available
  from ray.dashboard.tests.conftest import *
label_desc: Use image node_id 1 for calling a global function with example usage: _actor_killed(pid) and returns: False, True