Python metaprogramming for the win! Simple function to check is a given class has a subclass in the subclasses hierarchy chain.

issubsubclass.py

def issubsubclass(cls, subcls):
    """
    Recursively check if a given class has a subclass of `obj` class in the
    subclasses hierarchy.

    Under the hood, it does some metaprogramming magic recursively checking
    the `__bases__` magic attribute.

    Extends `issubclass` built-in function to check subclass hierarchies.

    Arguments:
        cls (class): class to check.
        subcls (class): class to lookup in the classes hierarchy.

    Returns:
        bool: `True` if it's the subclass is found, otherwise `False`.
    """
    if not cls:
        return False

    if issubclass(cls, subcls):
        return True

    if getattr(cls, '__bases__', None):
        return issubsubclass(cls.__bases__[0], subcls)

    return cls