Python 装饰@property 并接受参数的decorator

我的类(dataclass)有许多基于其他属性或dataclass个字段计算的属性.

我正在try 创建一个decorator，它获取所需字段或属性的列表.这意味着他们不能是None岁，也不能返回ValueError岁.如果其中任何一个是None，那么我想做点什么-为了简单起见，让我们raise ValueError(f'Missing {fieldname}').

def required_fields(required_fields):
    def _required_fields(f):
        def wrapper(self, *args, **kwargs):
            for field in required_fields:
                if getattr(self, field) is None:
                    raise ValueError(f"Missing {field}")
            return f
        return wrapper
    return _required_fields

编辑-再次try

def required_fields(required_fields):
    def _required_fields(f):
        @functools.wraps(f)
        def wrapper(self, *args, **kwargs):
            for field in required_fields:
                if getattr(self, field) is None:
                    raise ValueError(f"Missing {field}")
            return f(self, *args, **kwargs)
        return wrapper

Usage

@dataclasses.dataclass
class LoanCalculator:
    _amount: typing.Optional[M] = None
    _interest_rate: typing.Optional[M] = None
    _years: typing.Optional[M] = None
    _balance: typing.Optional[M] = None
    _payment_day: typing.Optional[int] = None
    _start_date: typing.Optional[datetime.date] = None

    class MissingDataError(Exception):
        pass

    @required_fields(['_interest_rate'])
    @property
    def monthly_interest_rate(self):
        return self._interest_rate / 12

我想在None时得到ValueError(f'Missing _interest_rate')，然后打monthly_interest_rate.

问题是根本没有调用包装器，我不知道如何继续.你能给我一些提示吗？