code: def test_is_group_initialized(ray_start_distributed_2_nodes, backend):
      world_size = 8
      actors, _ = create_collective_workers(world_size, backend=backend)
      # check group is_init
      actor0_is_init = ray.get(
          actors[0].report_is_group_initialized.remote()
      )
      assert actor0_is_init
      actor0_is_init = ray.get(
          actors[0].report_is_group_initialized.remote("random")
      )
      assert not actor0_is_init
      actor0_is_init = ray.get(
          actors[0].report_is_group_initialized.remote("123")
      )
      assert not actor0_is_init
      actor1_is_init = ray.get(
          actors[0].report_is_group_initialized.remote()
      )
      assert actor1_is_init
      actor1_is_init = ray.get(
          actors[0].report_is_group_initialized.remote("456")
      )
      assert not actor1_is_init
  
file_path: ray/python/ray/util/collective/tests/distributed_cpu_tests/test_distributed_basic_apis.py
imports: import pytest
  import ray
  from random import shuffle
  from ray.util.collective.types import Backend
  from ray.util.collective.tests.cpu_util import Worker, create_collective_workers
label_desc: Use image node_id 5 for calling a global function with example usage: test_is_group_initialized(ray_start_distributed_2_nodes, backend) without return types