public void should_create_valid_national_number()
        {
            var nationalNumber = NationalNumber.Create();

            var isValid = nationalNumber.IsValidNationalCode();

            Check.That(isValid).IsTrue();
        }
        public void should_return_true_in_validate_valid_nationalCode()
        {
            var isValidNationalNumber = NationalNumber.IsValid(NationalNumber.Create());

            Check.That(isValidNationalNumber).IsTrue();
        }