Error : Call to undefined method Laravel\Passport\Passport::routes()

The error happened when I was trying to use Laravel passport. I created Laravel project and installed Laravel Passport, and wrote this code for making route.

App\Providers\AuthServiceProvider.php

use Illuminate\Foundation\Support\Providers\AuthServiceProvider as ServiceProvider;
use Laravel\Passport\Passport;

class AuthServiceProvider extends ServiceProvider
{
・・・
    public function boot()
    {
        $this->registerPolicies();

        // wrote this
        if (! $this->app->routesAreCached()) {
            Passport::routes();
        }
    }
・・・
}

Then when I run this command,

$ php artisan make:controller AuthController

I got this error.

Call to undefined method Laravel\Passport\Passport::routes()

How to resolve

I found this question in this website and there is a correct answer.

The answer stated that since version 11, passport's routes have been moved to a dedicated route file, so I just removed this Passport::routes(), it was resolved.