所以我正在制作一個 Discord 機器人，并且我有兩個文件。一個稱為index.js，另一個稱為functions.js。如何在主程序中從functions.js 運行我的函數？const Discord = require('discord.js')const client = new Discord.Client()const { MessageEmbed } = require('discord.js')const config = require("./config.json");const sleep = require('sleep.js');const func = require('./functions');var days = 0;client.on("ready", () => {    console.log(`Bot has started, with ${client.users.cache.size} users, in ${client.channels.cache.size} channels of ${client.guilds.cache.size} guilds.`);    func.Christmas()    client.user.setActivity(days + ' days until Christmas!', { type: 'PLAYING', url: 'https://twitch.tv/itzp3nguin' });});client.login(config.token);如果我運行它，我會收到錯誤消息“func.Christmas”不是一個函數...Functions.js 文件： https: //pastebin.com/xsJbD1Qa