Fatal error: Uncaught Error: Call to undefined function add_action() in /home/oho09/public_html/lekcjatestdm/wp-content/themes/sydney/inc/integrations/lifter/class-sydney-lifterlms.php:37 Stack trace: #0 /home/oho09/public_html/lekcjatestdm/wp-content/themes/sydney/inc/integrations/lifter/class-sydney-lifterlms.php(26): Sydney_LifterLMS->__construct() #1 /home/oho09/public_html/lekcjatestdm/wp-content/themes/sydney/inc/integrations/lifter/class-sydney-lifterlms.php(218): Sydney_LifterLMS::get_instance() #2 {main} thrown in /home/oho09/public_html/lekcjatestdm/wp-content/themes/sydney/inc/integrations/lifter/class-sydney-lifterlms.php on line 37