如何在discord.py中执行ascii命令？

Question

我正在尝试在我的机器人中执行一个ascii命令，以将任何图像转换为ascii。我做了一些研究， 写这个：

    @commands.command(name='ascii')
    async def ascii(self, ctx, image_link: str=""):
        if not image_link:
            user = ctx.message.author
            image_link = user.avatar_url_as(size=1024)
        try:
            user = ctx.message.mentions[0]
            image_link = user.avatar_url_as(size=1024)
        except IndexError:
            pass

        url = 'https://useless-api--vierofernando.repl.co/imagetoascii'
        async with self.client.get(url, params={'image': str(image_link)}) as r:
            if r.status != 200:
                return await ctx.send("Failed :x:\nMaybe url is wrong :link:")
            else:
                result = await r.text()
                ascii_file = io.StringIO(result.replace('<br>', '\n'))

        em = discord.Embed(color=discord.Color(0xFFFF66))
        em.set_thumbnail(url=image_link)
        await ctx.send(file=discord.File(ascii_file, 'ascii.txt'), embed=em)

它不起作用。它总是说url错误。我不明白我在做什么错。