presto-main/src/main/java/io/prestosql/operator/aggregation/IntervalYearToMonthAverageAggregation.java/IntervalYearToMonthAverageAggregation/output
class IntervalYearToMonthAverageAggregation:    @OutputFunction(StandardTypes.INTERVAL_YEAR_TO_MONTH)
    public static void output(LongAndDoubleState state, BlockBuilder out)
    {
        long count = state.getLong();
        if (count == 0) {
            out.appendNull();
        }
        else {
            double value = state.getDouble();
            INTERVAL_YEAR_MONTH.writeLong(out, round(value / count));
        }
    }