title: TypeError: client.guilds is not iterable(14:29)
body: <p>I was adding new features to my Discord Bot then suddenly the following problem has stopped me from completing my code ! <strong><em>( What is my mistake ? Where is my mistake ? How can I solve it ? )</em></strong></p>
  
  <p><strong>The Problem :</strong> 
  <code>UnhandledPromiseRejectionWarning: TypeError: client.guilds is not iterable(14:29)</code></p>
  
  <p><strong>My Code :</strong> </p>
  
  <pre><code>    1: const { SettingProvider } = require("discord.js-commando");
      2: const File = require("./File.js");
      3: 
      4: module.exports = class JSONSettingsProvider extends SettingProvider {
      5:     constructor(path) {
      6:         super();
      7:         this.file = new File(path);
      8:         if (!this.file.exists) this.file.write({}, false, true);
      9:     }
      10: 
      11:     init(client) {
      12:         const data = this.file.read();
      13:         const id = bot.guild("689879529493233684");
      14:         for (const [id] of client.guilds) {
      15:             if (!data[id]) data[id] = {};
      16:             if (data[id].prefix &amp;&amp; client.guilds.has(id))
      17:                 client.guilds.get(id).commandPrefix = data[id].prefix;
      18:         }
      19:         this.file.write(data);
      20:     }
  </code></pre>