将选定的通道保留在discord.py循环之外

import discord
from discord.ext import commands

bot = commands.Bot(command_prefix='!')

selected_channel = None

@bot.command()
async def select_channel(ctx, channel_id):
    global selected_channel
    channel = bot.get_channel(int(channel_id))
    if channel:
        selected_channel = channel
        await ctx.send(f"Selected channel: {channel.name}")
    else:
        await ctx.send("Invalid channel ID")

@bot.command()
async def send_message(ctx, message):
    global selected_channel
    if selected_channel:
        await selected_channel.send(message)
    else:
        await ctx.send("No channel selected")