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

        add_action('admin_bar_menu', function () use ($identifier, $slug, $options) {
            global $wp_admin_bar;

            if ($slug === $identifier) {
                return;
            }

            // Get page identifier
            $pageid = $identifier.'-'.$slug;

            // Add child admin bar
            $wp_admin_bar->add_node([
                'parent'    => $identifier,
                'id'        => $pageid,
                'title'     => $options['title'],
                'href'      => admin_url('admin.php?page='.$pageid),
                'meta'      => false
            ]);
        });
    }