code: def test_reduce(self):
      for tensor_model_paralell_world_size in range(
          1, self.world_size + 1
      ):
          if self.world_size % tensor_model_paralell_world_size > 0:
              continue
          parallel_state.initialize_model_parallel(
              tensor_model_parallel_size_=tensor_model_paralell_world_size
          )
          t = torch.full(
              (10, 10, 10, 10), 50, device=f"cuda:{self.rank}"
          )
          expected = torch.full(
              (10, 10, 10, 10),
              50 * tensor_model_paralell_world_size,
              device=f"cuda:{self.rank}",
          )
          self.assertTrue(
              torch.equal(mappings._reduce(t), expected),
              msg=f"tensor_model_paralell_world_size: {tensor_model_paralell_world_size}",
          )
          parallel_state.destroy_model_parallel()
  
file_path: apex/tests/L0/run_transformer/test_mapping.py
imports: import logging
  import torch
  from torch.testing._internal import common_utils
  from apex.transformer import parallel_state
  from apex.transformer.tensor_parallel import mappings
  from apex.transformer.testing.distributed_test_base import NcclDistributedTestBase
  from apex.transformer.testing.distributed_test_base import UccDistributedTestBase
label_desc: Use image node_id 1 for calling the MappingTestBase obj's underlying member method code with example usage: obj.test_reduce() without return types