public async Task <Ship> PurchaseNewShip(string shipType)
 {
     if (kingdom.Id > 0 &&
         kingdom.Buildings.Any(b => b.Type == BuildingType.barracks) &&
         restrictionsService.FoodRateProduction(kingdom.Id) &&
         await restrictionsService.GoldAvailableForShips(kingdom.Id, shipType)
         )
     {
         return(await shipService.CreateNewShip(shipType));
     }
     return(null);
 }