public double nextDouble() {
        return real.nextDouble();
    }
@Test
    public void testRandomInt_int_int() {
        System.out.println("nextInt");
        int lo = -10;
        int hi = 20;
        smile.math.Random instance = new Random(System.currentTimeMillis());
        for (int i = 0; i < 1000000; i++) {
            double result = instance.nextDouble(lo, hi);
            assertTrue(result >= lo);
            assertTrue(result < hi);
        }
    }