No, it's a bad design that doesn't use type composition to restrict invalid representations. People are given type hints, but they still practice the same dynam

No, it's a bad design that doesn't use type composition to restrict invalid representations. People are given type hints, but they still practice the same dynamic typing mistakes as before, including the authors of the lib. Instead, it should distinguish between persisted entities and value objects: class Entity(Generic[A]): pk: int val: A class Hero: name: str secret_name: str age: None | int = None class Service(Generic[A]): def persist(self, x: A) -> Entity[A]: pk = self.execute(insert(x)) return Entity(pk, x) def select(self, *cond) -> Iterable[Entity[A]]: ... def copy(self, x: Entity[A]) -> Entity[A]: return self.persist(x.val) def delete(self, pk_ent: int | Entity[A]) -> A: ... It should be obvious how the same model extends to different PK types too: serial ints, UUIDs, etc.