public function exportFiles($content)
    {
        $content = $this->_defaultData($content);
        if ($content->file && (strpos($content->file, '/') === 0 || strpos($content->file, URL::to('/')) === 0)) {
            return [str_replace(URL::to('/'), '', $content->file)];
        } else {
            return [];
        }
    }