code: def redis_replicas(request, monkeypatch):
      if request.param:
          monkeypatch.setenv("TEST_EXTERNAL_REDIS_REPLICAS", "3")
      yield
  
imports: import contextlib
  import os
  import time
  import signal
  import sys
  import asyncio
  import async_timeout
  import pytest
  import ray
  import redis
  from ray._raylet import GcsClient
  import ray._private.gcs_utils
  from ray._private.test_utils import enable_external_redis, find_free_port, generate_system_config_map, async_wait_for_condition_async_predicate
  import ray._private.ray_constants
label_desc: Use image node_id 5 for calling a global function with example usage: redis_replicas(request, monkeypatch) without return types