code: def get_moe_group(moe_expert_count=2):
      """Return a process group for initializing a MoE layer."""
      if torch.distributed.is_initialized():
          world_size = torch.distributed.get_world_size()
  
          # If you have more experts than the world size.
          if world_size <= moe_expert_count:
              assert moe_expert_count % world_size == 0
              moe_groups = [[i] for i in range(world_size)]
  
          # If you have a larger world size than experts.
          else:
              assert world_size % moe_expert_count == 0
              ranks_per_group = world_size // moe_expert_count
              moe_groups = [
                  [
                      i + j * moe_expert_count
                      for j in range(ranks_per_group)
                  ]
                  for i in range(moe_expert_count)
              ]
  
          moe_pgs = [torch.distributed.new_group(g) for g in moe_groups]
  
          # Find the index in the set of moe_groups which contains the current rank.
          my_group_idx = _find_my_group_index(moe_groups)
          return moe_pgs[my_group_idx]
      else:
          return torch.distributed.new_group(
              [torch.distributed.get_rank()]
          )
  
imports: import copy
  import functools
  from time import time
  import unittest
  from parameterized import parameterized
  import torch
  from torch import nn
  from torch.optim import SGD, Adadelta, Adam
  from fairscale.fair_dev.testing.testing import dist_init, objects_are_equal, spawn_for_all_world_sizes
  from fairscale.internal.params import recursive_copy_to_device
  from fairscale.nn.data_parallel import FullyShardedDataParallel, get_fsdp_instances
  from fairscale.nn.data_parallel.fsdp_optim_utils import is_singleton_tensor
  from .test_fsdp import DistributedTest, DummyProcessGroup, MixtureOfExperts, TransformerWithSharedParams, rename_test, spawn_and_init
label_desc: Use image node_id 5 for calling a global function with example usage: get_moe_group(moe_expert_count) and returns: moe_pgs, torch