Harden the checks of the implementations of abstract classes

[tramora]

Description

We noticed that the checks for correct implementations of abstract classes are a bit lax.
An error is raised if an abstract method is effectively implemented in the child class but no check is done against the actual parameters

Questions/Ideas

@popescu-v proposed this snippet to check both the method and its exact parameters

from abc import ABC, abstractmethod

class MyBase(ABC):

    @abstractmethod
    def my_method(self, a: int, b: int) -> None:
        pass

    @classmethod
    def __subclasshook__(cls, subclass):
        if cls is MyBase:
            if 'my_method' in subclass.__dict__:
                method = subclass.__dict__['my_method']
                # Check if the method has the correct number of parameters
                if method.__code__.co_argcount == 3:  # 2 parameters + self
                    return True
            return False
        return NotImplemented

class ValidSubclass(MyBase):
    def my_method(self, a: int, b: int) -> None:
        pass

class InvalidSubclass(MyBase):
    def my_method(self, a: int) -> None:  # Incorrect number of parameters
        pass