Rop3.cs

Result ValidateEmail(Customer c) { ... }
Result ValidateNameSurname(Customer c) { ... }
Result SendEmail(Customer c) { ... }
Result SendEmailToCustomerIfValid(Customer c) { 
  var validateSurname = ValidateNameSurname(c);

  if(!validateSurname.Success)
    return validateSurname;

  var validateEmail = ValidateEmail(c);
  if(!validateEmail.Success)
    return validateEmail;

  return ValidateEmail(c);
}