Fatal error: Uncaught Error: Call to undefined function add_filter() in /var/www/esc.fs.cvut.cz/_HOSTING_WEB2_/wp-includes/default-filters.php:17 Stack trace: #0 {main} thrown in /var/www/esc.fs.cvut.cz/_HOSTING_WEB2_/wp-includes/default-filters.php on line 17