public static function parseSnsMessage(Message $snsMsg)
    {
        // Create the message and extract the information we need
        $ipnMsg = new Message($snsMsg->getMandatoryField("Message"));
        self::_addMetadataToIpnMessage(
            $ipnMsg, 
            $snsMsg->getNotificationMetadata()
        );
        return $ipnMsg;
    }