Laravel custom user verification email issue

In my laravel application i'm trying to create a customized user verification email template.

First I created a folder called, Notifications inside the App, Inside my Notifications folder I have a file called CustomVerifyEmailNotification.php

app/Notifications/CustomVerifyEmailNotification.php

Following is my code inside the CustomVerifyEmailNotification.php

<?php

namespace Illuminate\Auth\Notifications;

use Illuminate\Notifications\Messages\MailMessage;
use Illuminate\Notifications\Notification;
use Illuminate\Support\Carbon;
use Illuminate\Support\Facades\Config;
use Illuminate\Support\Facades\Lang;
use Illuminate\Support\Facades\URL;

class CustomVerifyEmailNotification extends Notification
{
    /**
     * The callback that should be used to build the mail message.
     *
     * @var \Closure|null
     */
    public static $toMailCallback;

    /**
     * Get the notification's channels.
     *
     * @param  mixed  $notifiable
     * @return array|string
     */
    public function via($notifiable)
    {
        return ['mail'];
    }

    /**
     * Build the mail representation of the notification.
     *
     * @param  mixed  $notifiable
     * @return \Illuminate\Notifications\Messages\MailMessage
     */
    public function toMail($notifiable)
    {
        $verificationUrl = $this->verificationUrl($notifiable);

        if (static::$toMailCallback) {
            return call_user_func(static::$toMailCallback, $notifiable, $verificationUrl);
        }

        return (new MailMessage)
            ->subject(Lang::get(''.('sentence.Verify Email Address').''))
            ->line(Lang::get(''.('sentence.If you did not create an account, no further action is required.').''));
    }

    /**
     * Get the verification URL for the given notifiable.
     *
     * @param  mixed  $notifiable
     * @return string
     */
    protected function verificationUrl($notifiable)
    {
        return URL::temporarySignedRoute(
            'verification.verify',
            Carbon::now()->addMinutes(Config::get('auth.verification.expire', 60)),
            [
                'id' => $notifiable->getKey(),
                'hash' => sha1($notifiable->getEmailForVerification()),
            ]
        );
    }

    /**
     * Set a callback that should be used when building the notification mail message.
     *
     * @param  \Closure  $callback
     * @return void
     */
    public static function toMailUsing($callback)
    {
        static::$toMailCallback = $callback;
    }
}

Then I changed my User.php according to following code

<?php

namespace App;

use App/Notifications/CustomVerifyEmailNotification;
use Illuminate\Contracts\Auth\MustVerifyEmail;
use Illuminate\Foundation\Auth\User as Authenticatable;
use Illuminate\Notifications\Notifiable;
use Laravel\Cashier\Billable;
use Spatie\Permission\Traits\HasRoles;

class User extends Authenticatable implements MustVerifyEmail
{
    use Notifiable,Billable;
    use HasRoles;

     public function sendEmailVerificationNotification() 
    {
        $this->notify(new CustomVerifyEmailNotification);
    }

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */

    protected $fillable = [
        'name','last_name', 'email', 'password','username','mobile','propic','user_roles','user_source',
    ];

    /**
     * The attributes that should be hidden for arrays.
     *
     * @var array
     */
    protected $hidden = [
        'password', 'remember_token',
    ];

    /**
     * The attributes that should be cast to native types.
     *
     * @var array
     */
    protected $casts = [
        'email_verified_at' => 'datetime',
    ];
}

But,

use App/Notifications/CustomVerifyEmailNotification;

showing me an error saying syntax error, unexpected '/', expecing ';' or ','

Because of that I'm also getting an error here

public function sendEmailVerificationNotification() 
    {
        $this->notify(new CustomVerifyEmailNotification);
    }

error is, undefined type 'App\CustomVerifyEmailNotification'

How can I fix this issue and create this custom verification email

I'm using laravel 6