public function postCampaignAttachments($campaignId, $data)
    {
        $url = $this->getApiEndpoint() . self::REST_CREATE_CAMPAIGN
            . "/$campaignId/attachments";
        $this->setUrl($url)
            ->setVerb('POST')
            ->buildPostBody($data);

        $result = $this->execute();

        if (isset($result->message)) {
            $this->helper->debug('postCampaignAttachments', [' CAMPAIGN ATTACHMENT ' .
                $result->message]);
        }

        return $result;
    }