private static void RentalRetrieve()
{
RentalManager rntlmngr = new RentalManager(new EfRentalDal());
var result = rntlmngr.GetByRentalİd(3);
Console.WriteLine(rntlmngr.CarRetrieve(result.Data).Message);
// Console.WriteLine(rntlmngr.Add(new Rental { Id = 3, CarId = 2, CustomerId = 2, RentDate = new DateTime(2021, 01, 26) }).Message);
}