private static void evaluateAndSavePredictions(Predictor predictor,
			List<Instance> instances, String predictions_file) throws IOException {
		PredictionsWriter writer = new PredictionsWriter(predictions_file);
		// TODO Evaluate the model if labels are available.
		AccuracyEvaluator e = new AccuracyEvaluator();
		System.out.println("The accuracy is: "+ e.evaluate(instances, predictor));
		for (Instance instance : instances) {
			Label label = predictor.predict(instance);
			writer.writePrediction(label);
		}
		writer.close();		
	}