def demo_paths(self):
        """returns collected demo paths excluding examples
        TODO: call super which returns custom paths in descriptor
        """
        base_path = os.path.join(self.module.__path__[0], 'demo')
        paths = []
        if os.path.isdir(base_path):
            for item in os.listdir(base_path):
                # TODO: support examples which is not auto-loaded
                if not os.path.isdir(os.path.join(base_path, 'examples')):
                    paths.append(os.path.join(base_path, item))
        return paths
returns collected demo paths excluding examples
        TODO: call super which returns custom paths in descriptor