code: def test_fp16_loss_scaler(self):
      with self.assertWarns(apex.DeprecatedFeatureWarning):
          apex.fp16_utils.LossScaler()
  
file_path: apex/tests/L0/run_deprecated/test_deprecated_warning.py
imports: import unittest
  import torch
  import apex
  from apex.transformer.testing.distributed_test_base import NcclDistributedTestBase
label_desc: Use image node_id 4 for calling the TestDeprecatedWarning obj's underlying member method code with example usage: obj.test_fp16_loss_scaler() without return types