code: def setUpClass(cls):
      cls.root_dir = cls.get_base_temp_dir()
      cls.samples_2spk = get_mock_dataset(cls.root_dir, 2)
      cls.samples_3spk = get_mock_dataset(cls.root_dir, 3)
  
file_path: audio/test/torchaudio_unittest/datasets/librimix_test.py
imports: import os
  from parameterized import parameterized
  from torchaudio.datasets import LibriMix
  from torchaudio_unittest.common_utils import get_whitenoise, save_wav, TempDirMixin, TorchaudioTestCase
label_desc: Use image node_id 1 for calling the TestLibriMix obj's underlying member method code with example usage: obj.setUpClass(cls) without return types