private void CheckValues(
            SignerLocation sl,
            DerUtf8String  countryName,
            DerUtf8String  localityName,
            Asn1Sequence   postalAddress)
        {
            if (countryName != null)
            {
                if (!countryName.Equals(sl.CountryName))
                {
                    Fail("countryNames don't match.");
                }
            }
            else if (sl.CountryName != null)
            {
                Fail("countryName found when none expected.");
            }

            if (localityName != null)
            {
                if (!localityName.Equals(sl.LocalityName))
                {
                    Fail("localityNames don't match.");
                }
            }
            else if (sl.LocalityName != null)
            {
                Fail("localityName found when none expected.");
            }

            if (postalAddress != null)
            {
                if (!postalAddress.Equals(sl.PostalAddress))
                {
                    Fail("postalAddresses don't match.");
                }
            }
            else if (sl.PostalAddress != null)
            {
                Fail("postalAddress found when none expected.");
            }
        }