Fatal error: Uncaught Error: Class "HTMLPurifier_AttrDef_HTML_Bool" not found in C:\WebServer\htdocs\bookshelf\vendor\xemlock\htmlpurifier-html5\library\HTMLPurifier\AttrDef\HTML\Bool2.php:12 Stack trace: #0 {main} thrown in C:\WebServer\htdocs\bookshelf\vendor\xemlock\htmlpurifier-html5\library\HTMLPurifier\AttrDef\HTML\Bool2.php on line 12