// Get Menus List from Restaurant
public static IO <List <Menu> > GetMenus(Restaurant restaurant)
=> from menus in Database.Query <FindMenusQuery, List <Menu> >(new FindMenusQuery(restaurant))
from getResult in RestaurantDomain.GetMenus(menus)
let agg = (getResult as GetMenusResult.GetMenusSuccessful)?.Menus
select agg;