private function parseResponseMessage($msg) {
        if (in_array($msg->status->groupId, [
            self::STATUS_GROUPS_UNDELIVERABLE, self::STATUS_GROUPS_EXPIRED,
            self::STATUS_GROUPS_REJECTED])) {
            $code = $msg->status->id;
            $text = sprintf("Error id=%d (groupId=%d). Message: %s",
                    $msg->status->id,
                    $msg->status->groupId,
                    $msg->status->description);
            $this->addError(new SendingError($msg->to, $code, $text));
            return false;
        }
        return true;
    }