# pylint: disable=missing-docstring,too-few-public-methods,line-too-long,useless-suppression from __future__ import annotations from typing import Generic, TypeVar T = TypeVar("T") class Coordinator(Generic[T]): def __init__(self, update_interval=None) -> None: self.update_interval = update_interval class Child(Coordinator[int | str]): # <-- 'int | str' here seems to be the issue def __init__(self) -> None: Coordinator.__init__(self, update_interval=2) # non-parent-init-called def _async_update_data(self): assert self.update_interval # access-member-before-definition self.update_interval = 1 # attribute-defined-outside-init