How to define type 'a child class of' in python?

Question

In the following example, the list1 attribute of P represents a list of instances of A.

class A:
   value1: str

class B(A):
   value2: str

class P:
   list1: List[A]

I want is to keep a list of child classes of A (not instances of A) in the variable list1. Is there a way to do it in python?

Answer 1

The solution is to use https://docs.python.org/3/library/typing.html#typing.Type.

from typing import List, Type

class P:
   list1: List[Type[A]]

Now, list1 represents a list of classes extended from A.