private FeatureArguments asFeatureArguments(Arguments arguments) {
        if (arguments.size() != 1)
            throw new IllegalArgumentException("A lightgbm node must take a single argument pointing to " +
                                               "the LightGBM model file under [application]/models");
        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/LightGBMFeatureConverter.java