如何在discord.py重写中使用类中的方法创建命令？

import discord
from discord.ext import commands

class MyBot(commands.Bot):
    def __init__(self, command_prefix):
        super().__init__(command_prefix)

    async def on_ready(self):
        print(f'Logged in as {self.user.name}')

    @commands.command()
    async def hello(self, ctx):
        await ctx.send('Hello, world!')

bot = MyBot(command_prefix='!')

bot.run('YOUR_BOT_TOKEN')