ارور Mailable class does not exist

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Mailable class does not exist

کد فایل EmailType

<?php
namespace App\Service\Notifaction\constants;
use App\Mail\ForgetPassword;
use App\Mail\TopicCreated;
use App\Mail\UserRegistered;
use App\User;
class EmailType{
    const USER_REGISTERED = 1;
    const TOPIC_CREATED = 2;
    const FORGET_PASSWORD = 3;
        public static function toString(){
            return [
                self::USER_REGISTERED => 'ثبت نام کاربر',
                self::TOPIC_CREATED => 'ایجاد مقاله جدید',
                self::FORGET_PASSWORD => 'فراموشی رمز عبور',
            ];
        }
        public static function toMail($type)
        {
          try {
            return [
                self::USER_REGISTERED => UserRegistered::class,
                self::TOPIC_CREATED => TopicCreated::class,
                self::FORGET_PASSWORD => ForgetPassword::class
        ][$type];
          } catch (\Throwable $th) {
                throw new \InvalidArgumentException('Mailable class does not exist');
          }
        }
}

کد NotifactionController

<?php
namespace App\Http\Controllers;
use App\Service\Notifaction\constants\EmailType;
use App\Service\Notifaction\Notifaction;
use App\User;
use Illuminate\Http\Request;
class NotifactionController extends Controller
{
    public function email(){
        $users = User::all();
        $emailType = EmailType::toString();
        return view('notifaction.send-email' , compact('users' , 'emailType'));
    }
    public function sendEmail(Request $request){
            $request->validate([
                    'user' => 'integer | exists:users,id',
                    'email_type' => 'integer'
            ]);
            $notifaction = resolve(Notifaction::class);
                $maillable = EmailType::toMail($request->email_type);
                $notifaction->sendEmail(User::find($request->user) , new $maillable);
            }
}

<div class="form-group"> <div class="col-ms-12"> <label for="email_type">@lang('notification.email_type')</label> <select class="form-control" name="email_type"> @foreach($emailType as $key => $type) <option value="{{$key}}">{{$type}}</option> @endforeach </select> </div> </div>

@extends('layouts.layout') @section('title' , 'خانه') @section('content') <div class="card"> <div class="card-header"> @lang('not.send_email') </div> <div class="card-body"> <form action="{{route('notifaction.send.email')}}" method="POST"> @csrf <div class="form-group"> <label for="users">کاربر ها</label> <select name="users" id="users" class="form-control"> @foreach($users as $user) <option value="{{$user->id}}">{{$user->name}}</option> @endforeach </select> </div> <div class="form-group"> <label for="email">ایمیل ها</label> <select name="email" id="email" class="form-control"> @foreach($emailTypes as $key => $type) <option value="{{$key}}">{{$type}}</option> @endforeach </select> </div> @if($errors->any()) <ul> @foreach($errors->all() as $error) <div class="small mb-2"> <li class="text-danager">{{$error}}</li> </div> @endforeach </ul> @endif <button name="send" class="btn btn-success">ارسال</button> </form> </div> </div> @endsection