code: def setUpClass(cls):
      cls.root_dir = cls.get_base_temp_dir()
      mocked_data = get_mock_dataset(cls.root_dir)
      cls.samples = mocked_data[0]
      cls.training = mocked_data[1]
      cls.validation = mocked_data[2]
      cls.testing = mocked_data[3]
  
file_path: audio/test/torchaudio_unittest/datasets/gtzan_test.py
imports: import os
  from pathlib import Path
  from torchaudio.datasets import gtzan
  from torchaudio_unittest.common_utils import get_whitenoise, normalize_wav, save_wav, TempDirMixin, TorchaudioTestCase
label_desc: Use image node_id 1 for calling the TestGTZAN obj's underlying member method code with example usage: obj.setUpClass(cls) without return types