code: def test_ray_client(call_ray_start):
      from ray.util.client import ray as ray_client
  
      ray.client("localhost:20000").connect()
  
      @ray.remote
      def f():
          return "hello client"
  
      assert ray_client.get(f.remote()) == "hello client"
  
file_path: ray/python/ray/tests/test_multi_node_2.py
imports: import logging
  import time
  import pytest
  import ray
  from ray._private.test_utils import SignalActor, generate_system_config_map, wait_for_condition
  from ray.autoscaler._private.monitor import Monitor
  from ray.autoscaler.sdk import request_resources
  from ray.cluster_utils import Cluster
  from ray.util.placement_group import placement_group, remove_placement_group
label_desc: Use image node_id 9 for calling a global function with example usage: test_ray_client(call_ray_start) and returns: str