<?phprequire_once 'HTMLPurifier/DefinitionCache.php';/** * Null cache object to use when no caching is on. */class HTMLPurifier_DefinitionCache_Null extends HTMLPurifier_DefinitionCache{        function add($def, $config) {        return false;    }        function set($def, $config) {        return false;    }        function replace($def, $config) {        return false;    }        function get($config) {        return false;    }        function flush($config) {        return false;    }        function cleanup($config) {        return false;    }    }