Fatal error: Uncaught Error: Call to undefined function add_filter() in /users/robiniffert95/www/gustavguns/wp-content/plugins/pelicula-core/inc/shortcodes/horizontal-timeline/horizontal-timeline.php:17 Stack trace: #0 {main} thrown in /users/robiniffert95/www/gustavguns/wp-content/plugins/pelicula-core/inc/shortcodes/horizontal-timeline/horizontal-timeline.php on line 17