Valueerror异常时使用json模块discord.py

我的意图是设置一道欢迎的消息时立即机器人加入，并能够改变它使用的命令分配。 这是我的代码:

import discord
from discord.ext import commands
import json

def get_welcomechannel(client, message,):
    with open('welcomechannel.json', 'r') as f:
        welcomechannel = json.load(f)
    
    return welcomechannel[str(message.guild.id)]
@client.event
async def on_guild_join(guild):
    general = find(lambda x: x.name == 'general',  guild.text_channels)
    if general and general.permissions_for(guild.me).send_messages:
        await general.send(f'Hello {guild.name}! My name is {client.user.name} and my prefix is ``?``! run ``?help`` to begin using me!')

    with open('prefixes.json', 'r') as f:
        prefixes = json.load(f)   
    prefixes[str(guild.id)] = "?"

    with open ('prefixes.json', 'w') as f:
        json.dump(prefixes, f, indent=4)

    with open('welcomechannel.json', 'r') as f:
        welcomechannel = json.load(f)   
    welcomechannel[str(guild.id)] = "general"

    with open ('prefixes.json', 'w') as f:
        json.dump(prefixes, f, indent=4)
@client.event
async def on_guild_remove(guild):
    with open('prefixes.json', 'r') as f:
        prefixes = json.load(f)   
    prefixes.pop(str(guild.id))

    with open ('prefixes.json', 'w') as f:
        json.dump(prefixes, f, indent=4)

    with open('welcomechannel.json', 'r') as f:
        welcomechannel = json.load(f)   
    welcomechannel.pop(str(guild.id))

    with open ('welcomechannel.json', 'w') as f:
        json.dump(welcomechannel, f, indent=4)
        print(f"{guild.name} kicked me!")


#rest of code here...

@client.command(name="changewelcomechannel")
async def changewelcomechannel(ctx, welcomechannel):
    with open('welcomechannel.json', 'r') as f:
        welcomechannel = json.load(f)   
    
    welcomechannel[str(ctx.guild.id)] = welcomechannel

    with open ('welcomechannel.json', 'w') as f:
        json.dump(welcomechannel, f, indent=4)
        await ctx.send(f"Welcome channel is now **{welcomechannel}**!"

但我得到这个错误：

 Ignoring exception in command changewelcomechannel:
2021-11-24T09:38:41.247854+00:00 app[worker.1]: Traceback (most recent call last):
2021-11-24T09:38:41.247927+00:00 app[worker.1]:   File "/app/.heroku/python/lib/python3.9/site-packages/discord/ext/commands/core.py", line 85, in wrapped
2021-11-24T09:38:41.247928+00:00 app[worker.1]:     ret = await coro(*args, **kwargs)
2021-11-24T09:38:41.247943+00:00 app[worker.1]:   File "/app/bot.py", line 352, in changewelcomechannel
2021-11-24T09:38:41.247943+00:00 app[worker.1]:     json.dump(welcomechannel, f, indent=4)
2021-11-24T09:38:41.247957+00:00 app[worker.1]:   File "/app/.heroku/python/lib/python3.9/json/__init__.py", line 179, in dump
2021-11-24T09:38:41.247958+00:00 app[worker.1]:     for chunk in iterable:
2021-11-24T09:38:41.247976+00:00 app[worker.1]:   File "/app/.heroku/python/lib/python3.9/json/encoder.py", line 431, in _iterencode
2021-11-24T09:38:41.247976+00:00 app[worker.1]:     yield from _iterencode_dict(o, _current_indent_level)
2021-11-24T09:38:41.248004+00:00 app[worker.1]:   File "/app/.heroku/python/lib/python3.9/json/encoder.py", line 405, in _iterencode_dict
2021-11-24T09:38:41.248005+00:00 app[worker.1]:     yield from chunks
2021-11-24T09:38:41.248018+00:00 app[worker.1]:   File "/app/.heroku/python/lib/python3.9/json/encoder.py", line 340, in _iterencode_dict
2021-11-24T09:38:41.248019+00:00 app[worker.1]:     raise ValueError("Circular reference detected")
2021-11-24T09:38:41.248041+00:00 app[worker.1]: ValueError: Circular reference detected

我没有完全错误代码当地所以我不得复制和粘贴的选择错误代码我可以找到。

我用同样的结构中另一个命令和它的工作很好。 我不是那么有经验的与使用id模块在蟒蛇，所以如果有人可以帮助，这将是可怕的。 非常感谢

编辑：我终于意识到我做了什么错，我是应该使用的另一个变量

welcomechannel[str(ctx.guild.id)] = welcomechannel# this is supposed to be the new variable#