Fatal error: Uncaught Error: Interface "UsingInterfaces\ProductInterface" not found in C:\xampp\htdocs\swagger\vendor\zircote\swagger-php\Examples\using-interfaces\Product.php:8 Stack trace: #0 {main} thrown in C:\xampp\htdocs\swagger\vendor\zircote\swagger-php\Examples\using-interfaces\Product.php on line 8