def read_args(parser):
    """Return a ``dict`` of arguments from an ``ArgumentParser``.

    Parses arguments using ``parser.parse_args()`` and returns a ``dict`` of
    all arguments that are not ``None``.
    """
    args = parser.parse_args()
    args_dict = vars(args)
    return {k: v for k, v in args_dict.items() if v is not None}