public function removeNotification($notification)
    {
        $ids = clone $this->notificationIds;
        $ids->offsetUnset($notification->id);
        $this->set('notificationIds', $ids);

        $ids = clone $this->newNotificationIds;
        $ids->offsetUnset($notification->id);
        $this->set('newNotificationIds', $ids);

        $notification->removeSubscribers(array($this->_mixer));
    }