https://medium.com/p/9b20df89c285

exemplo3.php

<?php

protected function createProduct()
{
    return Product::create($this->request->all());
}
protected function applyDiscount($type, $product)
{
    $discount = Discount::byType($type);

    $discount->applyDiscountForProduct($product);
}
protected function notifyUsersVia($method)
{
    $users = User::all();

    foreach ($users as $user) {
        $notification = Notification::via($method);
        $notification->notifyUser($user);
    }
}