def build_args(parser):
    """Constructs the command-line arguments for ``index2color``."""
    parser.add_argument(
        "--in-dir",
        required=True,
        type=str,
        help="Path to directory with dataset",
    )
    parser.add_argument(
        "--out-labeling", required=True, type=str, help="Path to output JSON"
    )
    parser.add_argument(
        "--num-workers",
        default=1,
        type=int,
        help="Number of workers to parallel the processing",
    )

    return parser