Get class-level class list, including all super class's.

def get_class_list(cls) -> DOMTokenList:
        """Get class-level class list, including all super class's."""
        cl = []
        cl.append(DOMTokenList(cls, cls.class_))
        if cls.inherit_class:
            for base_cls in cls.__bases__:
                if issubclass(base_cls, WdomElement):
                    cl.append(base_cls.get_class_list())
        # Reverse order so that parent's class comes to front  <- why?
        cl.reverse()
        return DOMTokenList(cls, *cl)