code: def tearDownClass(cls):
      # In case of test failure
      cls.librispeech_cls._ext_audio = ".flac"
  
file_path: audio/test/torchaudio_unittest/datasets/librispeech_test_impl.py
imports: import os
  from pathlib import Path
  from torchaudio.datasets import librispeech
  from torchaudio_unittest.common_utils import get_whitenoise, normalize_wav, save_wav, TempDirMixin
label_desc: Use image node_id 2 for calling the LibriSpeechTestMixin obj's underlying member method code with example usage: obj.tearDownClass(cls) without return types