private FeatureArguments asFeatureArguments(Arguments arguments) {
        if (arguments.isEmpty())
            throw new IllegalArgumentException("An ONNX node must take an argument pointing to " +
                                               "the ONNX model file under [application]/models");
        if (arguments.expressions().size() > 3)
            throw new IllegalArgumentException("An onnx feature can have at most 3 arguments");

        return new FeatureArguments(arguments);
    }
A cache of imported models indexed by model path. This avoids importing the same model multiple times.
config-model/src/main/java/com/yahoo/schema/expressiontransforms/OnnxFeatureConverter.java