def METHOD_NAME(parser, is_train=True):
    """Add new model-specific options and rewrite default values for existing options.
    Parameters:
        parser -- the option parser
        is_train -- if it is training phase or test phase. You can use this flag to add training-specific or test-specific options.
    Returns:
        the modified parser.
    """
    parser.set_defaults(dataset_mode='aligned')  # You can rewrite default values for this model. For example, this model usually uses aligned dataset as its dataset.
    if is_train:
        parser.add_argument('--lambda_regression', type=float, default=1.0, help='weight for the regression loss')  # You can define new arguments for this model.
    return parser