/**
  * Removes instance from local store.
  *
  * @param int Dataform id.
  * @param string Instance type name.
  * @return void.
  */
 public static function unregister($dataformid = 0, $manager = null)
 {
     if (!$dataformid) {
         self::$instances = array();
     } else {
         if (!$manager) {
             unset(self::$instances[$dataformid]);
         } else {
             unset(self::$instances[$dataformid][$manager]);
         }
     }
 }