code: public PushedNotifications getSuccessfulNotifications() {
  		PushedNotifications filteredList = new PushedNotifications(this);
  		for (PushedNotification notification : this) {
  			if (notification.isSuccessful()) filteredList.add(notification);
  		}
  		return filteredList;
  	}
docs: Filter a list of pushed notifications and return only the ones that were successful.
  
  @return a filtered list containing only notifications that were succcessful