@ConstantFunction(name = "quarters_add", argTypes = {DATETIME, INT}, returnType = DATETIME, isMonotonic = true)
    public static ConstantOperator quartersAdd(ConstantOperator date, ConstantOperator quarter) {
        return ConstantOperator.createDatetimeOrNull(
                date.getDatetime().plus(quarter.getInt(), IsoFields.QUARTER_YEARS));
    }
@Test
    public void quartersAdd() {
        assertEquals("2015-06-23T09:23:55",
                ScalarOperatorFunctions.quartersAdd(O_DT_20150323_092355, O_INT_1).getDatetime().toString());
    }