public function addChild($slug, $options)
    {
        $identifier = $this->getModel()->getIdentifier();

        // Check slug
        if (empty($slug)) {
            throw new AdminPageException(Translate::t('adminpage.errors.slug_is_not_defined'));
        }

        // Set default option's values
        $defaults = [
            'slug'          => $slug,

            // Page options
            'title'         => Translate::t('adminpage.child.defaults.title'),
            'name'          => Translate::t('adminpage.child.defaults.name'),
            'description'   => '',
            'sections'      => [],

            // Options
            'capabilities'  => OL_ZEUS_WP_CAP,
            'adminbar'      => true,
            'submit'        => true,
        ];

        // Merge options
        $options = array_merge($defaults, $options);
        $this->getModel()->updatePage($slug, $options);

        $pageid = $slug === $identifier ? $identifier : $identifier.'-'.$slug;

        // Add child page
        add_submenu_page(
            $identifier,
            $options['title'],
            $options['name'],
            $options['capabilities'],
            $pageid,
            [&$this, 'callback']
        );

        // Add admin bar menu
        if ($options['adminbar']) {
            $this->addChildAdminBar($slug, $options);
        }
    }