public function whereUsedMetaBox()
    {
        if (empty(self::$enabled)) {
            return;
        }

        global $post;
        $module = $this;

        if (is_null($post)) {
            return;
        }

        $usage = self::getModuleUsage($post->ID);

        add_meta_box('modularity-usage', 'Module usage', function () use ($module, $usage) {
            if (count($usage) == 0) {
                echo '<p>' . __('This modules is not used yet.', 'modularity')  . '</p>';
                return;
            }

            echo '<p>' . __('This module is used on the following places:', 'modularity') . '</p><p><ul class="modularity-usage-list">';

            foreach ($usage as $page) {
                echo '<li><a href="' . get_permalink($page->post_id) . '">' . $page->post_title . '</a></li>';
            }

            echo '</ul></p>';
        }, self::$enabled, 'side', 'default');
    }