presto-main/src/main/java/io/prestosql/type/DateTimeOperators.java/DateTimeOperators/datePlusIntervalYearToMonth
class DateTimeOperators:    @ScalarOperator(ADD)
    @SqlType(StandardTypes.DATE)
    public static long datePlusIntervalYearToMonth(@SqlType(StandardTypes.DATE) long left, @SqlType(StandardTypes.INTERVAL_YEAR_TO_MONTH) long right)
    {
        long millis = MONTH_OF_YEAR_UTC.add(TimeUnit.DAYS.toMillis(left), right);
        return TimeUnit.MILLISECONDS.toDays(millis);
    }