presto-orc/src/main/java/io/prestosql/orc/metadata/statistics/BooleanStatisticsBuilder.java/BooleanStatisticsBuilder/mergeBooleanStatistics
class BooleanStatisticsBuilder:    public static Optional<BooleanStatistics> mergeBooleanStatistics(List<ColumnStatistics> stats)
    {
        BooleanStatisticsBuilder booleanStatisticsBuilder = new BooleanStatisticsBuilder();
        for (ColumnStatistics columnStatistics : stats) {
            BooleanStatistics partialStatistics = columnStatistics.getBooleanStatistics();
            if (columnStatistics.getNumberOfValues() > 0) {
                if (partialStatistics == null) {
                    // there are non null values but no statistics, so we can not say anything about the data
                    return Optional.empty();
                }
                booleanStatisticsBuilder.addBooleanStatistics(columnStatistics.getNumberOfValues(), partialStatistics);
            }
        }
        return booleanStatisticsBuilder.buildBooleanStatistics();
    }