private static void RentalTest()
        {
            RentalManager rentalManager = new RentalManager(new EFRentalDal());

            var rentalAdded = rentalManager.Add(new Rental {
                CarId = 4, CustomerID = 1, RentDate = DateTime.Now, ReturnDate = null
            });;

            Console.WriteLine(rentalAdded.Message);
            var rentalDetailGet = rentalManager.GetAllCarDetails();

            foreach (var rentalDetail in rentalDetailGet.Data)
            {
                Console.WriteLine(rentalDetail.CustomerFirstName);
                Console.WriteLine(rentalDetail.CustomerLastName);
                Console.WriteLine(rentalDetail.CarDescription);
                Console.WriteLine(rentalDetail.BrandName);
                Console.WriteLine(rentalDetail.ColorName);
                Console.WriteLine(rentalDetail.CarDailyPrice);
                Console.WriteLine(rentalDetail.RentDate);
                Console.WriteLine(rentalDetail.ReturnDate);
            }
        }