Fatal error: Uncaught Error: Call to undefined function apply_filters() in /home/malvernj/public_html/wp-content/plugins/event-tickets/src/admin-views/commerce/metabox/sku.php:11 Stack trace: #0 {main} thrown in /home/malvernj/public_html/wp-content/plugins/event-tickets/src/admin-views/commerce/metabox/sku.php on line 11