Making a list of all classnames in the Python inheritance tree

Question

My end goal is to try an alternative way to make type equality tests at runtime by checking an ancestor list of all the classnames. This does require that I own all the classes I want to typecheck this way and that's ok. The way I'm calling super here isn't quite right, but maybe there's a better way to create this list.

This would allow me to replace my existing
isinstance(x, Child) checks with Child.__name__ in x.typetags()

class HasTypeTags():
    @classmethod
    def typetags(cls):
        try:
            return cls._typetags
        except:
            cls._typetags = [cls.__name__]
            for base in cls.__bases__:
                cls._typetags.append(base.__name__)
            try:
                cls._typetags += super(cls, cls).typetags()
            except:
                pass
                
            return cls._typetags

class Root(HasTypeTags, object):
    pass

class Child(Root):
    pass

class GrandChild(Child):
    pass


grandchild = GrandChild()
print(grandchild.typetags())
# should output something like ['GrandChild', 'Child', 'Root', 'HasTypeTags', 'object']
# but actually prints ['GrandChild', 'Child', 'GrandChild', 'Child']