[Python] How to type function which returns associated type so that it works in subclass?

I have a class Foo which has a to_bar method which returns Bar. I also have a subclass MyFoo for which to_bar returns MyBar (a subclass of Bar). Foo has quite a lot of methods which can return Bar, and for each one of these, the corresponding method on MyFoo should return MyBar.

Here's what I've written:

from __future__ import annotations

class Foo:
def __init__(self, value):
self.value = value

@property
def _bar(self) -> type[Bar]:
return Bar

def to_bar(self) -> Bar:
return self._bar(self.value)

class Bar:
def __init__(self, value):
self.value = value

class MyFoo(Foo):
@property
def _bar(self) -> type[MyBar]:
return MyBar

class MyBar(Bar):
...

print(type(Foo(3).to_bar()))
print(type(MyFoo(3).to_bar()))


It outputs

$ python t.py
<class '__main__.Bar'>
<class '__main__.MyBar'>


which is correct. All good so far.

BUT, if I add

reveal_type(Foo(3).to_bar())
reveal_type(MyFoo(3).to_bar())


to the end of the file and run mypy on it, I get

$ mypy t.py
t.py:28: note: Revealed type is "t.Bar"
t.py:29: note: Revealed type is "t.Bar"
Success: no issues found in 1 source file


How can I type to_bar such that the return value is going to be correct for MyFoo.to_bar? I could overwrite to_bar in MyFoo, but doing so for every method which returns Bar in Foo would be tedious and error-prone

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