Fatal error: Uncaught Braintree\Exception: The Braintree library requires the xmlwriter extension. in /var/www/html/old code/Example_BT_EC/braintree-php-3.28.0/lib/Braintree.php:18 Stack trace: #0 /var/www/html/old code/Example_BT_EC/braintree-php-3.28.0/lib/Braintree.php(24): Braintree::requireDependencies() #1 /var/www/html/old code/Example_BT_EC/doPayment.php(28): require_once('...') #2 {main} thrown in /var/www/html/old code/Example_BT_EC/braintree-php-3.28.0/lib/Braintree.php on line 18