code: def test_actor_lifetime_load_balancing(ray_start_cluster):
      cluster = ray_start_cluster
      cluster.add_node(num_cpus=0)
      num_nodes = 3
      for i in range(num_nodes):
          cluster.add_node(num_cpus=1)
      ray.init(address=cluster.address)
  
      @ray.remote(num_cpus=1)
      class Actor:
          def __init__(self):
              pass
  
          def ping(self):
              return
  
      actors = [Actor.remote() for _ in range(num_nodes)]
      ray.get([actor.ping.remote() for actor in actors])
  
imports: import os
  import sys
  import time
  import numpy
  import pytest
  import ray
  import ray._private.gcs_utils
  from ray.util.state import list_actors
  import ray.cluster_utils
  from ray._private.test_utils import SignalActor, convert_actor_state, kill_actor_and_wait_for_failure, make_global_state_accessor, run_string_as_driver, wait_for_condition, wait_for_pid_to_exit
  from ray._private.ray_constants import gcs_actor_scheduling_enabled
  from ray.experimental.internal_kv import _internal_kv_get, _internal_kv_put
label_desc: Use image node_id 4 for calling a global function with example usage: test_actor_lifetime_load_balancing(ray_start_cluster) without return types