Fatal error: Uncaught Braintree\Exception: The Braintree library requires the xmlwriter extension. in /var/www/html/old code/Example_BT_ECBT_Vault/braintree_php-master/lib/Braintree.php:18 Stack trace: #0 /var/www/html/old code/Example_BT_ECBT_Vault/braintree_php-master/lib/Braintree.php(24): Braintree::requireDependencies() #1 /var/www/html/old code/Example_BT_ECBT_Vault/doPayment.php(31): require_once('...') #2 {main} thrown in /var/www/html/old code/Example_BT_ECBT_Vault/braintree_php-master/lib/Braintree.php on line 18