How to use the santd.Menu.MenuItemGroup function in santd

<span>{{leafItem.name}}</span>
                        
                    
                    
                        <span>{{item.name}}</span>
                    
                
            
        
    `;

    static components = {
        's-menu': Menu,
        's-sub-menu': Menu.Sub,
        's-menu-item': Menu.Item,
        's-menu-item-group': Menu.MenuItemGroup
    };

    static computed = {
        defaultOpenKeys() {
            const routes = this.data.get('routes');
            return routes.map(item =&gt; item.key);
        },
        selectedKeys() {
            return [this.data.get('currentPath')];
        },
        count() {
            let routes = this.data.get('routes').filter(route =&gt; route.list);
            let count = 0;
            routes.forEach(route =&gt; {
                route.list.forEach(r =&gt; {
                    count += r.leaf.length;