docs: private Response serveOneOrAll(List<water.ModelMetrics> list) {
      JsonArray metricsArray = new JsonArray();
  
      for (water.ModelMetrics metrics : list) {
        JsonObject metricsJson = metrics.toJSON();
        metricsArray.add(metricsJson);
      }
  
      JsonObject result = new JsonObject();
      result.add("metrics", metricsArray);
      return Response.done(result);
    }