代码 `examples/ding-dong-bot.py`存在bug

```
        # file_box = FileBox.from_url(
        #     'https://ss3.bdstatic.com/70cFv8Sh_Q1YnxGkpoWK1HF6hhy/it/'
        #     'u=1116676390,2305043183&fm=26&gp=0.jpg',
        #     name='ding-dong.jpg'
        # )
        # await msg.say(file_box)
```
该段代码中会导致报错