code: def _collect_data(directory):
    
    # Returns:
    data_files = []
    transcripts = [
        filename for filename in os.listdir(directory)
        if filename.endswith(".csv")
    ]
    for transcript in transcripts:
      transcript_path = os.path.join(directory, transcript)
      with open(transcript_path, "r") as transcript_file:
        transcript_reader = csv.reader(transcript_file)
        # skip header
        _ = next(transcript_reader)
        for transcript_line in transcript_reader:
          media_name, label = transcript_line[0:2]
          filename = os.path.join(directory, media_name)
          data_files.append((media_name, filename, label))
    return data_files
docs: Traverses directory collecting input and target files.
  
    Args:
     directory: base path to extracted audio and transcripts.
    Returns:
     list of (media_base, media_filepath, label) tuples