docstr: Test checkpoint with BF16 model
code: def test_checkpoint_bf16(self):
      """Test checkpoint with BF16 model"""
      self.test_checkpoint(
          rtol=5e-2,
          atol=1e-5,
          save_model_kwargs=dict(
              model_dtype=torch.bfloat16,
              optim_dtype=torch.float32,
              param_sync_dtype=torch.bfloat16,
              store_params=False,
              store_param_remainders=True,
          ),
          load_model_kwargs=dict(
              model_dtype=torch.bfloat16,
              optim_dtype=torch.float32,
              param_sync_dtype=torch.bfloat16,
              store_params=False,
              store_param_remainders=True,
          ),
      )
  
imports: from contextlib import contextmanager
  import io
  from typing import Callable, Optional, Tuple
  import unittest
  import warnings
  import torch
  from torch.testing._internal import common_utils
  from apex.transformer.testing.distributed_test_base import NcclDistributedTestBase
label_desc: Use image node_id 22 for calling the TestDistributedFusedAdam obj's underlying member method code with example usage: obj.test_checkpoint_bf16() without return types