code: def _maybe_convert_wav(mp3_filename, wav_filename):
      if not os.path.exists(wav_filename):
          transformer = sox.Transformer()
          transformer.convert(
              samplerate=SAMPLE_RATE, n_channels=CHANNELS
          )
          try:
              transformer.build(mp3_filename, wav_filename)
          except sox.core.SoxError:
              pass
  
file_path: DeepSpeech/bin/import_cv2.py
imports: import csv
  import os
  import subprocess
  import unicodedata
  from multiprocessing import Pool
  import progressbar
  import sox
  from deepspeech_training.util.downloader import SIMPLE_BAR
  from deepspeech_training.util.importers import get_counter, get_imported_samples, get_importers_parser, get_validate_label, print_import_report
  from ds_ctcdecoder import Alphabet
label_desc: Use image node_id 5 for calling a global function with example usage: _maybe_convert_wav(mp3_filename, wav_filename) without return types