Return Subclass instance from Base class

Summary

TLDR: I have an ABC with severel subclasses. The ABC has a method that returns a subclass instance. I want to put the ABC and the subclasses in distinct files.

Example

In one file, this works:

from abc import ABC, abstractmethod


class Animal(ABC):

    # Methods to be implemented by subclass.

    @property
    @abstractmethod
    def name(self) -> str:
        """Name of the animal."""
        ...

    @abstractmethod
    def action(self):
        """Do the typical animal action."""
        ...

    # Methods directly implemented by base class.

    def turn_into_cat(self):
        return Cat(self.name)


class Cat(Animal):
    def __init__(self, name):
        self._name = name

    name = property(lambda self: self._name)
    action = lambda self: print(f"{self.name} says 'miauw'")


class Dog(Animal):
    def __init__(self, name):
        self._name = name

    name = property(lambda self: self._name)
    action = lambda self: print(f"{self.name} says 'woof'")

>>> mrchompers = Dog("Mr. Chompers")

>>> mrchompers.action()
Mr. Chompers says 'woof'

>>> mrchompers.turn_into_cat().action()
Mr. Chompers says 'miauw'

Issue

I want to put the Animal class definition in base.py, and the Cat and Dog class definitions in subs.py.

The problem is, that this leads to cyclic imports. base.py must include a from .subs import Cat, and subs.py must include a from .base import Animal.

I've incountered cyclic import errors before, but usually when type hinting. In that case I can put the lines

from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from .base import Animal

However, that is not the case here.

Any ideas as to how to split this code up into 2 files?

source https://stackoverflow.com/questions/70716070/return-subclass-instance-from-base-class