class DateOfBirthPIDTransformer implements PIDTransformer {

    @Override
    public List<String> toHL7(PatientInfo patientInfo) {
        notNull(patientInfo, "patientInfo cannot be null");
        String date = patientInfo.getDateOfBirth();
        return StringUtils.isEmpty(date) ? null : Collections.singletonList(date);
    }

}