docs: public String getAsSimpleString() {
          String rewardString = "";
          for (Map.Entry<Integer, Float> entry : this.map.entrySet()) {
              Integer dimension = entry.getKey();
              Float reward_value = entry.getValue();
              if (!rewardString.isEmpty())
                  rewardString += ",";
              rewardString += dimension + ":" + reward_value;
          }
          return rewardString;
      }