public Car GetCarById(string id)
        {
            var dataCar = new CarRental.BuissnessLogic.CarService();
            var car     = dataCar.GetCarById(Convert.ToInt32(id));

            return(car);
        }
        public Car GetCarById(int id)
        {
            var dataCar = new CarRental.BuissnessLogic.CarService();
            var car     = dataCar.GetCarById(id);

            if (car is null)
            {
                throw new NullReferenceException("there is not car with that ID");
            }

            return(car);
        }