MailingTable::getMailingSiteId

static function getMailingSiteId($mailingId)
{
	static $cache;
	if (!$cache || !($cache[$mailingId] ?? false))
	{
		$mailing = self::getById($mailingId)->fetch();
		$cache[$mailingId] = $mailing['SITE_ID'];
	}

	return $cache[$mailingId];
}