code: def test_device_placement(self):
      # valid devices
      DevicePlacementSpec("cuda:0")
      DevicePlacementSpec(torch.device(0))
      DevicePlacementSpec(torch.device("cuda:0"))
      DevicePlacementSpec("rank:0/cuda:0")
      DevicePlacementSpec("rank:0/cpu")
      DevicePlacementSpec("rank:0")
  
      # invalid devices
      with self.assertRaisesRegex(
          ValueError, "Could not parse remote_device"
      ):
          DevicePlacementSpec("cuda:foo")
      with self.assertRaisesRegex(
          ValueError, "Could not parse remote_device"
      ):
          DevicePlacementSpec("foo:0")
      with self.assertRaisesRegex(
          RuntimeError, "Invalid device string"
      ):
          DevicePlacementSpec("rank:0/cuda:foo")
      with self.assertRaisesRegex(
          RuntimeError, "Invalid device string"
      ):
          DevicePlacementSpec("rank:0/cpu2")
  
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 1 for calling the TestShardingSpec obj's underlying member method code with example usage: obj.test_device_placement() without return types