code: def test_actor_method(ray_start_2_cpus):
      ag = ActorGroup(actor_cls=DummyActor, num_actors=2)
      assert ray.get(ag.return_arg.remote(1)) == [1, 1]
  
file_path: ray/python/ray/tests/test_actor_group.py
imports: import time
  import warnings
  import pytest
  import ray
  from ray.util.actor_group import ActorGroup
label_desc: Use image node_id 5 for calling a global function with example usage: test_actor_method(ray_start_2_cpus) without return types