public LossFunction getLossFunction() {
    Object lossFunction = get("loss_function");

    try {
      if (lossFunction == null) {
        throw new NullPointerException();
      }

      return (LossFunction) lossFunction;
    } catch (RuntimeException re) {
      throw new IllegalArgumentException(
          "The loss function object ("
              + ClassDictUtil.formatClass(lossFunction)
              + ") is not a LossFunction or is not a supported LossFunction subclass",
          re);
    }
  }
 public List<? extends Number> getPriors() {
   return (List) ClassDictUtil.getArray(this, "priors");
 }