private void AddBillingOfficePhone(BillingOfficePhoneDto billingOfficePhoneDto, BillingOffice billingOffice)
        {
            var phoneType = _mappingHelper.MapLookupField <BillingOfficePhoneType> (billingOfficePhoneDto.BillingOfficePhoneType);

            var phoneNumber = new PhoneBuilder()
                              .WithPhoneNumber(billingOfficePhoneDto.PhoneNumber)
                              .WithPhoneExtensionNumber(billingOfficePhoneDto.Extension)
                              .Build();

            var billingOfficePhone = new BillingOfficePhone(phoneType, phoneNumber);

            billingOffice.AddPhoneNumber(billingOfficePhone);
        }
 private static void RemoveBillingOfficePhone(
     BillingOfficePhoneDto billingOfficePhoneDto, BillingOffice billingOffice, BillingOfficePhone billingOfficePhone)
 {
     billingOffice.RemovePhoneNumber(billingOfficePhone);
 }
 private void ChangeBillingOfficePhone(
     BillingOfficePhoneDto billingOfficePhoneDto, BillingOffice billingOffice, BillingOfficePhone billingOfficePhone)
 {
     RemoveBillingOfficePhone(billingOfficePhoneDto, billingOffice, billingOfficePhone);
     AddBillingOfficePhone(billingOfficePhoneDto, billingOffice);
 }