Fatal error: Uncaught Error: Class 'WP_List_Table' not found in /home/Szyna/public_html/stroneczka/wp-admin/includes/class-wp-ms-themes-list-table.php:17 Stack trace: #0 {main} thrown in /home/Szyna/public_html/stroneczka/wp-admin/includes/class-wp-ms-themes-list-table.php on line 17