code: def _saveWavFolders(self, root_dir, labels, how_many):
      wav_data = self._getWavData()
      for label in labels:
          dir_name = os.path.join(root_dir, label)
          os.mkdir(dir_name)
          for i in range(how_many):
              file_path = os.path.join(
                  dir_name, "some_audio_%d.wav" % i
              )
              self._saveTestWavFile(file_path, wav_data)
  
file_path: tensorflow-upstream/tensorflow/examples/speech_commands/wav_to_features_test.py
imports: import os
  import tensorflow
  from tensorflow.examples.speech_commands import wav_to_features
  from tensorflow.python.framework import test_util
  from tensorflow.python.platform import test
label_desc: Use image node_id 3 for calling the WavToFeaturesTest obj's underlying member method code with example usage: obj._saveWavFolders(root_dir, labels, how_many) without return types