How to type hint a method that returns a subclass?-CodePudding

I have the setup

import typing

class A:
    def get_b(self) -> B: # <- ERROR: B is not defined yet
       return b # <- and instance of B here

class B(A): # <- subclass of A, defined after A is defined
    pass

Is there a clean way to type hint the method get_b?

Edit: thanks to the wonderful answers, this problem is not really addressed in the documentation, but in some PEPs, one of them is the problem of forward declarations

CodePudding user response：

You can put B in quotes like:

class A:
    def get_b(self) -> 'B':
       return b

class B(A):
    pass