@Override
  public PolyStringType clone() {
    PolyStringType poly = new PolyStringType();
    poly.setNorm(getNorm());
    poly.setOrig(getOrig());
    copyContent(getAny(), poly.getAny());

    return poly;
  }
 public PolyStringType plus(PolyStringType operand) {
   if (operand == null) {
     return this;
   }
   return new PolyStringType(getOrig() + operand.getOrig());
 }