presto-ml/src/main/java/io/prestosql/plugin/ml/RegressorFeatureTransformer.java/RegressorFeatureTransformer/RegressorFeatureTransformer
class RegressorFeatureTransformer:    public RegressorFeatureTransformer(Regressor regressor, FeatureTransformation transformation)
    {
        this.regressor = requireNonNull(regressor, "regressor is null");
        this.transformation = requireNonNull(transformation, "transformation is null");
    }