public static function toArray($object, $group = NULL, $filter = NULL)
	{
		if ($object === null) {
			return null;
		}
		if (!isset(self::$groups[$group])) {
			throw new \InvalidArgumentException('Group \'' . $group . '\' not supported for ' . 'Skrz\\Meta\\Fixtures\\Protobuf\\ClassWithNoProperty' . '.');
		} else {
			$id = self::$groups[$group];
		}

		if (!($object instanceof ClassWithNoProperty)) {
			throw new \InvalidArgumentException('You have to pass object of class Skrz\Meta\Fixtures\Protobuf\ClassWithNoProperty.');
		}

		if (Stack::$objects === null) {
			Stack::$objects = new \SplObjectStorage();
		}

		if (Stack::$objects->contains($object)) {
			return null;
		}

		Stack::$objects->attach($object);

		try {
			$output = array();

		} catch (\Exception $e) {
			Stack::$objects->detach($object);
			throw $e;
		}

		Stack::$objects->detach($object);
		return $output;
	}