def _objcls_2_abstract(obj_cls):
    """Converts object class to abstract."""
    name = obj_cls['name']
    abstract = {
        'must': obj_cls.get('must', []),
        'may': obj_cls.get('may', []),
        'desc': obj_cls.get('desc', ''),
        'idx': obj_cls['idx'],
    }

    return (name, abstract)