code: def test_init_multiple_groups(
      ray_start_distributed_2_nodes, world_size, backend
  ):
      num_groups = 5
      actors = [Worker.remote() for _ in range(world_size)]
      for i in range(num_groups):
          group_name = str(i)
          init_results = ray.get(
              [
                  actor.init_group.remote(
                      world_size,
                      i,
                      group_name=group_name,
                      backend=backend,
                  )
                  for i, actor in enumerate(actors)
              ]
          )
          for j in range(world_size):
              assert init_results[j]
  
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 2 for calling a global function with example usage: test_init_multiple_groups(ray_start_distributed_2_nodes, world_size, backend) without return types