presto-main/src/main/java/io/prestosql/operator/scalar/DateTimeFunctions.java/DateTimeFunctions/lastDayOfMonthFromTimestampWithTimeZone
class DateTimeFunctions:    @Description("last day of the month of the given timestamp")
    @ScalarFunction("last_day_of_month")
    @SqlType(StandardTypes.DATE)
    public static long lastDayOfMonthFromTimestampWithTimeZone(@SqlType(StandardTypes.TIMESTAMP_WITH_TIME_ZONE) long timestampWithTimeZone)
    {
        long millis = unpackMillisUtc(timestampWithTimeZone - MILLISECONDS_IN_DAY);
        millis = unpackChronology(timestampWithTimeZone).monthOfYear().roundCeiling(millis);
        return MILLISECONDS.toDays(millis);
    }