public Model requireModel(String name) {
        Model model = models.get(name);
        if (model == null)
            throw new IllegalArgumentException("No model named '" + name + "'. Available models: " +
                                               String.join(", ", models.keySet()));
        return model;
    }
Returns the given model, or throws a IllegalArgumentException if it does not exist
model-evaluation/src/main/java/ai/vespa/models/evaluation/ModelsEvaluator.java