https://www.v2ex.com/t/804745

like_js5.py

# 重度采用词法作用域。这对 Python 不友好，尤其因为有内部指针循环引用，回收依赖新 GC。

class Account:
    def __init__(self, **kwargs):
        self._is_valid = True

        def valid_before_logout(func):
            def wrapped(*args, **kwargs):
                if self._is_valid:
                    return func(*args, **kwargs)
                else:
                    raise ValueError('not valid')

            return wrapped

        @valid_before_logout
        def refresh():
            pass

        @valid_before_logout
        def invalidate():
            self._is_valid = False

        @valid_before_logout
        def signout():
            self._is_valid = False

        self.refresh = refresh
        self.invalidate = invalidate
        self.signout = signout

normal.py

# Pythonic

def valid_before_logout(func):
    def wrapped(self, *args, **kwargs):
        if self._is_valid:
            return func(self, *args, **kwargs)
        else:
            raise ValueError('not valid')

    return wrapped


class Account:
    def __init__(self, **kwargs):
        self._is_valid = True

    @valid_before_logout
    def refresh(self):
        pass

    @valid_before_logout
    def invalidate(self):
        self._is_valid = False

    @valid_before_logout
    def signout(self):
        self._is_valid = False