Braintree requires xmlwriter

Hi,

I’m getting the below errors after installing your plugin.

My Setup:
-Wordpress Version: 4.9.8
-PHP Version: PHP7.0
-xmlwriter is installed
-Apache2
-OS Ubuntu 16.04

ERROR MESSAGES
—————————————————————————————
Fatal error: Uncaught Braintree\Exception: The Braintree library requires the xmlwriter extension. in /var/www/wordpress/alphanode.online/public_html/wp-content/plugins/wp-e-commerce/wpsc-components/merchant-core-v3/libraries/pp-braintree/sdk/lib/Braintree.php:18

Stack Trace
1.
PPrequireDependencies()
/var/www/wordpress/alphanode.online/public_html/wp-content/plugins/wp-e-commerce/wpsc-components/merchant-core-v3/libraries/pp-braintree/sdk/lib/Braintree.php:23
2.
require_once(‘/var/www/wordpr…’)
/var/www/wordpress/alphanode.online/public_html/wp-content/plugins/wp-e-commerce/wpsc-components/merchant-core-v3/libraries/pp-braintree/pp-braintree.php:39
3.
WPEC_Braintree_Helpers::includes()
/var/www/wordpress/alphanode.online/public_html/wp-content/plugins/wp-e-commerce/wpsc-components/merchant-core-v3/libraries/pp-braintree/pp-braintree.php:20
4.
WPEC_Braintree_Hel in /var/www/wordpress/alphanode.online/public_html/wp-content/plugins/wp-e-commerce/wpsc-components/merchant-core-v3/libraries/pp-braintree/sdk/lib/Braintree.php on line 18
/var/www/wordpress/alphanode.online/public_html/wp-content/plugins/wp-e-commerce/wpsc-components/merchant-core-v3/gateways/braintree-credit-cards.php:8