Metaclass to add class attrs

metaattrs.py

class Meta1(type):
    @classmethod
    def __prepare__(cls, *args):
        return {"decorator": lambda f: f, "prepared_attr": "prepared_attr_value"}


class Meta2(type):
    def __new__(cls, name, bases, namespace):
        namespace["decorator"] = lambda f: f
        namespace["new_attr"] = "new_attr_value"
        return super().__new__(cls, name, bases, namespace)


class Test1(metaclass=Meta1):
    prep = prepared_attr

    @decorator
    def f(self):
        print(self.__class__.prepared_attr)


class Test2(metaclass=Meta2):
    prep = new_attr

    @decorator
    def f(self):
        print(self.__class__.new_attr)


t1 = Test1()
t1.f()

t2 = Test2()  # NameError: name 'new_attr' is not defined