}  if (username != null && checkIfUsernameExists(username, thisPerson)) { throw new DomainException("error.person.existent.username"); }
}
    private void checkConditionsToCreateNewPerson(final String username, final String documentIDNumber,            final IDDocumentType documentType, Person thisPerson) {        if (documentIDNumber != null                && documentType != null                && checkIfDocumentNumberIdAndDocumentIdTypeExists(documentIDNumber, documentType,                        thisPerson)) {            throw new DomainException("error.person.existent.docIdAndType");        }        if (username != null && checkIfUsernameExists(username, thisPerson)) {            throw new DomainException("error.person.existent.username");        }    }