Discordチャンネルの過去投稿をチェックしてアラートを飛ばすPythonコード

import discord, datetime

TOKEN = 'トークン'
log_channel_id = 監視対象のチャンネルID
alert_channel_id = 通知を送りたいチャンネルID

intents = discord.Intents.default()
intents.message_content = True
client = discord.Client(intents=intents)

author_list = ["監視対象のユーザー名"]

@client.event
async def on_ready():
    log_channel = client.get_channel(log_channel_id)
    alert_channel = client.get_channel(alert_channel_id)

    async for message in log_channel.history(limit=30):
        if(len(author_list) != 0):
            if((datetime.datetime.now(datetime.timezone.utc) - message.created_at).seconds <= 10800):
                for i, author in enumerate(author_list):
                    if(author in str(message.author)):
                        del author_list[i]
            else:
                break
        else:
            await log_channel.send("Complete")
            await client.close()

    for author in author_list:
        await alert_channel.send("Alert-" + author)

    await client.close()

client.run(TOKEN)