code: def test_get_chunk_sharding_params(self):
      ranks = [
          "rank:0/cuda:0",
          "rank:1/cuda:1",
          "rank:2/cuda:2",
          "rank:3/cuda:3",
      ]
      spec = ChunkShardingSpec(
          dim=0,
          placements=ranks,
      )
      result = get_chunk_sharding_params(21, 4, spec, 1)
      self.assertEqual(6, result[0])
      self.assertEqual(6, result[1])
      result = get_chunk_sharding_params(21, 4, spec, 3)
      self.assertEqual(18, result[0])
      self.assertEqual(3, result[1])
      ranks[1], ranks[2] = ranks[2], ranks[1]
      ranks[0], ranks[3] = ranks[3], ranks[0]
      spec.placements = ranks
      result = get_chunk_sharding_params(21, 4, spec, 1)
      self.assertEqual(12, result[0])
      self.assertEqual(6, result[1])
      result = get_chunk_sharding_params(21, 4, spec, 3)
      self.assertEqual(0, result[0])
      self.assertEqual(6, result[1])
  
imports: from typing import List, Union
  from dataclasses import dataclass
  import copy
  import torch
  from torch.testing._internal.common_utils import TestCase
  from torch.testing._internal.common_distributed import requires_nccl, skip_if_lt_x_gpu
  from torch.distributed._shard import sharded_tensor, _shard_tensor
  from torch.distributed._shard.sharding_spec import ShardingSpec, ChunkShardingSpec, DevicePlacementSpec, EnumerableShardingSpec, ShardMetadata, _infer_sharding_spec_from_shards_metadata
  from torch.distributed._shard.sharded_tensor import TensorProperties, ShardedTensor, ShardedTensorMetadata
  from torch.distributed._shard.sharding_spec._internals import check_tensor, get_split_size, get_chunked_dim_size, get_chunk_sharding_params, validate_non_overlapping_shards_metadata
  from torch.testing._internal.common_cuda import TEST_MULTIGPU
  from torch.testing._internal.common_utils import run_tests, skip_but_pass_in_sandcastle_if
  from torch.testing._internal.distributed._shard.sharded_tensor._test_st_common import _chunk_sharding_specs_list_for_test
  from torch.testing._internal.distributed._shard.sharded_tensor import ShardedTensorTestBase, with_comms
label_desc: Use image node_id 6 for calling the TestShardingSpec obj's underlying member method code with example usage: obj.test_get_chunk_sharding_params() without return types