nickname = value([registration_attrs["nickname"], Registration.nickname(registration)])
email = value([registration_attrs["email"], Registration.email(registration)])
name = value([registration_attrs["name"], Registration.name(registration)]) || nickname
nickname = value([registration_attrs["nickname"], Registration.nickname(registration)])
email = value([registration_attrs["email"], Registration.email(registration)])
name = value([registration_attrs["name"], Registration.name(registration)]) || nickname