Use Laravel's Factories with custom main namespace on Laravel 8

AppServiceProvider.php

<?php

/**
*** On Laravel 8, factories becomes classes.
*** If your are using a custom namespace for your app, you need to add Factory::guessFactoryNamesUsing.
*** There is an example, enjoy 🎊
**/

namespace CustomNamespace\Providers;

use Illuminate\Support\ServiceProvider;
use Illuminate\Database\Eloquent\Factories\Factory;

class AppServiceProvider extends ServiceProvider
{
    /**
     * Register any application services.
     *
     * @return void
     */
    public function register()
    {
        //
    }

    public function boot()
    {
        Factory::guessFactoryNamesUsing(function (string $model) {
            return 'Database\Factories\\' . class_basename($model) . 'Factory';
        });
    }
}