dog_meta.py

class DogMeta(type):
    def __new__(cls, name, bases, dct):
        print(f">> DogMeta __new__: {name}")
        print(f">> DogMeta __new__: {bases}")
        print(f">> DogMeta __new__: {dct}")
        x = super().__new__(cls, name, bases, dct)
        x.race = "Dog"
        return x


class Dog(metaclass=DogMeta):
    def init(self, name) -> None:
        print(f"Dog init -> {name}")
        self.name = name

    def bark(self) -> None:
        print(f"Dog bark! {self.name}")


d = Dog()
d.init("Rex")
d.bark()

OtherDog = DogMeta("OtherDog", (), {"name": "OtherRex"})
od = OtherDog()
print(od.name, od.race)

##
#  >> DogMeta __new__: Dog
#  >> DogMeta __new__: ()
#  >> DogMeta __new__: {'__module__': '__main__', '__qualname__': 'Dog', 'init': <function ...>, 'bark': <function ...>}
#  Dog init -> Rex
#  Dog bark! Rex
#  >> DogMeta __new__: OtherDog
#  >> DogMeta __new__: ()
#  >> DogMeta __new__: {'name': 'other'}
#  other Dog