如何在discord.py的循环中发送消息？

import discord
import asyncio

client = discord.Client()

@client.event
async def on_ready():
    print('Bot已登录')

@client.event
async def on_message(message):
    if message.content.startswith('!send_message'):
        channel = message.channel
        await channel.send('这是一条消息')

async def my_background_task():
    await client.wait_until_ready()
    while not client.is_closed():
        channel = client.get_channel(1234567890)  # 替换为你想要发送消息的频道ID
        await channel.send('这是一条定时发送的消息')
        await asyncio.sleep(60)  # 每隔60秒发送一次消息

client.loop.create_task(my_background_task())
client.run('YOUR_BOT_TOKEN')  # 替换为你的Bot Token