Fatal error: Uncaught Error: Class "HTMLPurifier_Filter" not found in /srv/www/htdocs/moodle/lib/htmlpurifier/HTMLPurifier/Filter/ExtractStyleBlocks.php:25 Stack trace: #0 {main} thrown in /srv/www/htdocs/moodle/lib/htmlpurifier/HTMLPurifier/Filter/ExtractStyleBlocks.php on line 25