langchain/chains/query_constructor/parser.py/get_parser
def get_parser(
    allowed_comparators: Optional[Sequence[Comparator]] = None,
    allowed_operators: Optional[Sequence[Operator]] = None,
) -> Lark:
    transformer = QueryTransformer(
        allowed_comparators=allowed_comparators, allowed_operators=allowed_operators
    )
    return Lark(GRAMMAR, parser="lalr", transformer=transformer, start="program")