docs: public String getAsXMLString() {
          // Create a string XML representation:
          String rewardString = null;
          try {
              rewardString = SchemaHelper.serialiseObject(this.getAsReward(), Reward.class);
          } catch (JAXBException e) {
              System.out.println("Caught reward serialization exception: " + e);
          }
          return rewardString;
      }