public void Validate()
{
var expireOn = new DateTime(ExpireYear, ExpireMonth, 1).AddMonths(1).AddDays(-1);
Contract.Assert(!string.IsNullOrWhiteSpace(FirstName));
Contract.Assert((!Initial.HasValue) || char.IsUpper(Initial.Value));
Contract.Assert(!string.IsNullOrWhiteSpace(LastName));
Contract.Assert(Email.IsEmail());
Contract.Assert(Phone.IsPhone(PhoneKind.EitherFormat));
Contract.Assert(Global.CountryCodes.Contains(Country));
Contract.Assert(Address1.IsTrimmed(100));
Contract.Assert(string.IsNullOrEmpty(Address2) || Address2.IsTrimmed(100));
Contract.Assert(City.IsTrimmed(50));
Contract.Assert(State.IsTrimmed(100));
Contract.Assert(PostalCode.IsTrimmed(100));
Contract.Assert(CardNumber.IsCardNumber());
Contract.Assert((CVV2 >= 100) && (CVV2 <= 9999));
Contract.Assert(expireOn >= DateTime.Today);
Details.ForEach(detail => detail.Validate());
}