/**
  * Singleton access.
  *
  * @return Codendi_HTMLPurifier
  */
 public static function instance()
 {
     if (!isset(self::$Codendi_HTMLPurifier_instance)) {
         $c = __CLASS__;
         self::$Codendi_HTMLPurifier_instance = new $c();
     }
     return self::$Codendi_HTMLPurifier_instance;
 }