Storage::getInstance

static function getInstance($fUserId, $siteId)
{
	if (empty($fUserId))
	{
		throw new MainArgumentNullException('fUserId');
	}

	if (empty($siteId))
	{
		throw new MainArgumentNullException('siteId');
	}

	$hash = static::getHash($fUserId, $siteId);

	if (!isset(static::$instance[$hash]))
	{
		static::$instance[$hash] = new static($fUserId, $siteId);
	}

	return static::$instance[$hash];
}