def parse_args(parser):
    """
    Parse commandline arguments.
    """
    parser.add_argument('-i', '--input', type=str, required=True,
                        help='path to the input text files')
    parser.add_argument('-o', '--output', required=True,
                        help='output folder to save text files')
    parser.add_argument('-a', '--audio', required=True,
                        help='audio folder to save wavs files')
    parser.add_argument('-m', '--mels', required=True,
                        help='mels folder to save pt files')

    return parser