getMailingVoucher example

$config = $inheritance->buildConfig(
            $shop->getTemplate(),
            $shop,
            false
        );

        $user = $this->getMailingUserByEmail(Shopware()->Config()->get('Mail'));
        $template->assign('sUser', $user, true);
        $hash = $this->createHash((int) $user['mailaddressID'], (int) $mailing['id']);
        $template->assign('sCampaignHash', $hash, true);
        $template->assign('sRecommendations', $this->getMailingSuggest($mailing['id'], $user['userID']), true);
        $template->assign('sVoucher', $this->getMailingVoucher($mailing['id']), true);
        $template->assign('sCampaign', $this->getMailingDetails($mailing['id']), true);
        $template->assign('sConfig', Shopware()->Config());
        $template->assign('sBasefile', Shopware()->Config()->get('BaseFile'));
        $template->assign('theme', $config);

        $templatePath = 'newsletter/index/' . $mailing['template'];

        if (!empty($mailing['plaintext'])) {
            $templatePath = 'newsletter/alt/' . $mailing['template'];
        }