function iterateWithCallback($callback)
 {
     $r = new ArrayObject_PartyCal();
     $i = $this->getIterator();
     while ($i->valid()) {
         $r->append(call_user_func($callback, $i->key(), $i->current()));
         $i->next();
     }
     return $r;
 }
 /**
  *
  */
 public function __construct(Config_PartyCal $config)
 {
     parent::__construct($config->getArrayCopy());
 }