from dataclasses import dataclass
from typing import Type


class EntityMeta(type):
    def __new__(mcs, name: str, bases: tuple, namespace: dict) -> Type['Entity']:
        cls = super().__new__(mcs, name, bases, namespace)
        return dataclass(cls)


class Entity(metaclass=EntityMeta):
    pass


class User(Entity):
    name: str
    age: int


print(User('Seba', 26))