Suppose we need to add support to the CashRegister class from the preceding problem to enable the cashier to quickly undo the preceding purchase that may have been entered incorrectly. This will require the use of a third instance variable to keep track of the previous purchase. Complete the class with above specification.

What did i do wrong with this const discord = require('discord.js'); var bot = new discord.client(); const token = 'ntm3mjcxmtu1mjg3ote2ntq2.dyogew.dpfiwfpuifzuzvifop-csuxasnm' const prefix = "! " bot.registry.registergroup('simple', 'simple'); bot.registry.registerdefaults(); bot.registry. + '/commands'); bot.on('message', message => { if(message.content == 'hi! ') { message.channel.send ('@everyone sup, how is @everyone day going'); } if(message.content == 'h3lp') { message.channel.send ('dose not have any commands yet'); } bot.on('ready', function() { console.log("ready") }); bot.login(token);