presto-ml/src/main/java/io/prestosql/plugin/ml/MLFunctions.java/MLFunctions/regress
class MLFunctions:    @ScalarFunction
    @SqlType(StandardTypes.DOUBLE)
    public static double regress(@SqlType(MAP_BIGINT_DOUBLE) Block featuresMap, @SqlType(RegressorType.NAME) Slice modelSlice)
    {
        FeatureVector features = ModelUtils.toFeatures(featuresMap);
        Model model = getOrLoadModel(modelSlice);
        checkArgument(model.getType().equals(REGRESSOR), "model is not a regressor");
        Regressor regressor = (Regressor) model;
        return regressor.regress(features);
    }