def sanitize_list_input(_list: list, _def: list) -> list:
    """Sanitize the _list by reducing it to distinct values.
    If _list is None, then return second parameters value _def

    :param _list: list, if not None, will be reduced to its distinct values
    :param _def: list, the value to be returned, if _list is None
    :return: Either sanitized _list or _def value, if _list is None
    """
    if not _list:
        return [_def]
    else:
        return list(set(_list))