discord.ext.commands.errors.CommandInvokeError：命令引发异常：NameError：未定义名称'main' SQLlite3

Question

我正在尝试使用 sqllite 将用户的 id 上传到数据库，但是每当我运行代码并执行命令时，它都会显示此错误

discord.ext.commands.errors.CommandInvokeError：命令引发异常：NameError：名称“main”未定义

    async def add(self, ctx, user:discord.User):
        if ctx.message.author.guild_permissions.manage_messages:
            db = sqlite3.connect('main.sqlite')
            cursor = main.cursor()
            cursor.execute(f"SELECT Players FROM main")
            result = cursor.fetchall()
            if result != user.id:
                sql = ("INSERT INTO main(Players) VALUES(?)")
                val = (user.id)
                await ctx.send(f"<@!{user.id}> has been added")
            else:
                await ctx.send(f"<@{user.id}> is already in teh database")
            cursor.execute(sql,val)
            db.commit()
            cursor.close()
            db.close()