Discord python 在角色授予事件上

Question

所以我一直试图让机器人在成员获得角色时宣布，我知道这段代码可能根本没有意义，但这就是我问的原因：我该怎么做？

@bot.event

async def on_member_update(before, after):

    if str(after.roles) == 'android':

        fmt = "{0.mention} your role request has been accepted! :confetti_ball: You've been granted the role '{1}'"

        await bot.send_message(bot.get_channel('495285593711050754'), fmt.format(member, after.roles.name))

        print(colored('moderation.clf: ', 'blue'), colored('Android granted', 'white'))

    if str(after.roles) == 'human':

        fmt = "{0.mention} your role request has been accepted! :confetti_ball: You've been granted the role '{1}'"

        await bot.send_message(bot.get_channel('495285593711050754'), fmt.format(member, after.roles.name))

        print(colored('moderation.clf: ', 'blue'), colored('Human granted', 'white'))

    if str(after.roles) == 'moderator':

        fmt = "{0.mention} you are now part of the CyberLife staff, we're so excited to have you here! :confetti_ball:"

        await bot.send_message(bot.get_channel('495285593711050754'), fmt.format(member, after.roles.name))

        print(colored('moderation.clf: ', 'blue'), colored('Moderator granted', 'white'))