class MyDef(type):

    def __new__(cls, class_name, class_attr, class_dic):

        upper_data = {}

        for k,v in class_dic.items():

            if not callable(v) and not k.startswith('__'):

                upper_data[k.upper()] = v

            else:

                upper_data[k] = v

        return type.__new__(cls, class_name, class_attr, upper_data)

class People(metaclass=MyDef):

    time = 'now'

    work = 'weekends'

print(People.__dict__)

class MyDef(type):

    def __call__(self, *args, **kwargs):

        if args:

            raise TypeError(' must use keyword argument')

        obj = object.__new__(self)

        for k,v in kwargs.items():

            obj.__dict__[k.upper()] = v

        return obj

class People(metaclass=MyDef):

    tag = 'China'

    some = 'None'

p1 = People(name = 'panda')

print(p1.__dict__)

# 在元类中控制自定义的类产生的对象相关的属性全部为隐藏属性

class Mymeta(type):

    def __init__(self, class_name, class_bases, attr):

        super(Mymeta, self).__init__(class_name, class_bases, attr)

    def __call__(self, *args, **kwargs):

        obj = self.__new__(self)

        self.__init__(obj, *args, **kwargs )

        obj.__dict__ = {'_%s__%s' % (self.__name__, k): v for k, v in obj.__dict__.items()}

        return obj

class P(metaclass=Mymeta):

    def __init__(self, name, age):

        self.name = name

        self.age = age

p1 = P('','')

print(p1._P__name)