public function listing($contenttype)
    {
        $templates = [];

        // First candidate: defined specifically in the contenttype.
        if (!empty($contenttype['listing_template'])) {
            $templates[] = $contenttype['listing_template'];
        }

        // Second candidate: a template with the same filename as the name of
        // the contenttype.
        $templates[] = $contenttype['slug'] . '.twig';

        // Third candidate: Theme-specific config.yml file.
        if ($template = $this->config->get('theme/listing_template')) {
            $templates[] = $template;
        }

        // Fourth candidate: Global config.yml
        $templates[] = $this->config->get('general/listing_template');

        // Fifth candidate: fallback to 'listing.twig'
        $templates[] = 'listing.twig';

        return $templates;
    }