A descriptor that permits a different type in the setter

typed_property.py

from __future__ import annotations

from typing import NamedTuple, cast, overload


class ConsoleDimensions(NamedTuple):
    width: int
    height: int


class Size:
    def __set_name__(self, owner: type[object], name: str) -> None:
        self.name = name

    @overload
    def __get__(self, obj: None, objtype: None) -> Size:
        ...

    @overload
    def __get__(self, obj: object, objtype: type[object]) -> ConsoleDimensions:
        ...

    def __get__(
        self, obj: object | None, objtype: type[object] | None = None
    ) -> Size | ConsoleDimensions:
        if obj is None:
            return self
        return cast(ConsoleDimensions, obj.__dict__[self.name])

    def __set__(self, obj: object, value: ConsoleDimensions | tuple[int, int]) -> None:
        if isinstance(value, tuple):
            value = ConsoleDimensions(*value)
        obj.__dict__[self.name] = value


class Console:
    size = Size()

    def __init__(self) -> None:
        self.size = ConsoleDimensions(80, 25)


console = Console()
print(console.size)

console.size = (10, 20)
print(console.size)

console.size = ConsoleDimensions(3, 4)
print(console.size)