private static void transformGeneratedFunction(ModelStore store,
                                                   Set<String> constantsReplacedByFunctions,
                                                   String functionName,
                                                   RankingExpression expression) {

        expression = replaceConstantsByFunctions(expression, constantsReplacedByFunctions);
        store.writeFunction(functionName, expression);
    }
Returns the expression matching the given arguments.
config-model/src/main/java/com/yahoo/vespa/model/ml/ConvertedModel.java