@Override
    public int hashCode() {
        int result = firstName != null ? firstName.hashCode() : 0;
        result = 31 * result + (lastName != null ? lastName.hashCode() : 0);
        result = 31 * result + (patronymic != null ? patronymic.hashCode() : 0);
        result = 31 * result + (DOB != null ? DOB.hashCode() : 0);
        result = 31 * result + (passportNumber != null ? passportNumber.hashCode() : 0);
        result = 31 * result + (identificationNumber != null ? identificationNumber.hashCode() : 0);
        result = 31 * result + (address != null ? address.hashCode() : 0);
        return result;
    }