Fatal error: Uncaught Error: Class "PayPal\Api\Refund" not found in C:\xampp\htdocs\wp-content\plugins\nextgen-gallery-pro\modules\paypal_checkout\vendor\paypal\rest-api-sdk-php\lib\PayPal\Api\DetailedRefund.php:20 Stack trace: #0 {main} thrown in C:\xampp\htdocs\wp-content\plugins\nextgen-gallery-pro\modules\paypal_checkout\vendor\paypal\rest-api-sdk-php\lib\PayPal\Api\DetailedRefund.php on line 20