How to use the aiocqhttp.message.Message._split_iter function in aiocqhttp

def __add__(self, other: Any):
        result = Message(self)
        try:
            if isinstance(other, Message):
                result.extend(other)
            elif isinstance(other, MessageSegment):
                result.append(other)
            elif isinstance(other, list):
                result.extend(map(lambda d: MessageSegment(d), other))
            elif isinstance(other, dict):
                result.append(MessageSegment(other))
            elif isinstance(other, str):
                result.extend(Message._split_iter(other))
            return result
        except:
            pass
        raise ValueError('the addend is not a valid message')