class MyGeneric[T]: # ill-defined, what's the type of MySequence.example? example: ClassVar[Self] # error: ClassVar cannot contain Self type in generic classes

class MyGeneric[T]: pre_method_hooks: ClassVar[list[ Callable[[Self], None] ]] = []

from typing import Callable, ClassVar, Self, Any from abc import abstractmethod class Transform[X, Y]: pre_transform_hooks: ClassVar[list[Callable[[Self], None]]] = [] # ❌️ def __init_subclass__(cls) -> None: super().__init_subclass__() original_transform = cls.transform def wrapped_transform(self: Self, x: X, /, *args: Any, **kwargs: Any) -> Y: for hook in cls.pre_transform_hooks: hook(self) return original_transform(self, x, *args, **kwargs) cls.transform = wrapped_transform # type: ignore[method-assign] @abstractmethod def transform(self, x: X, /) -> Y: ... class Demo(Transform[int, int]): def transform(self, x: int, /) -> int: return 0 def hello_world(self) -> None: print(f"Hello, world! from {self}") pre_transform_hooks: ClassVar[list[Callable]] = [hello_world] Demo().transform(0) # prints "Hello, world! from <__main__.Demo object at ...>"