Fatal error: Uncaught Error: Class "MercadoPago\Entity" not found in C:\xampp\htdocs\addfirst\vendor\mercadopago\dx-php\src\MercadoPago\Entities\DiscountCampaign.php:18 Stack trace: #0 {main} thrown in C:\xampp\htdocs\addfirst\vendor\mercadopago\dx-php\src\MercadoPago\Entities\DiscountCampaign.php on line 18