code: def docker_cluster(head_node, worker_node):
      yield (head_node, worker_node)
  
file_path: ray/python/ray/tests/conftest_docker.py
imports: import time
  import pytest
  from pytest_docker_tools import container, fetch, network, volume
  from pytest_docker_tools import wrappers
  import subprocess
  from typing import List
label_desc: Use image node_id 1 for calling a global function with example usage: docker_cluster(head_node, worker_node) without return types