public SimpleImputer(Map<String, Object> values) {
        this.values = values;
    }
@Test
    public void testSimpleImputer() throws Exception {
        System.out.println("SimpleImputer");
        double[][] data = SyntheticControl.x;
        DataFrame df = DataFrame.of(data);
        SimpleImputer simpleImputer = SimpleImputer.fit(df);
        Function<double[][], double[][]> imputer = x -> simpleImputer.apply(DataFrame.of(x)).toArray();

        impute(imputer, data, 0.01, 38.88);
        impute(imputer, data, 0.05, 48.80);
        impute(imputer, data, 0.10, 45.04);
    }