presto-main/src/main/java/io/prestosql/sql/planner/iterative/rule/MultipleDistinctAggregationToMarkDistinct.java/MultipleDistinctAggregationToMarkDistinct/hasMultipleDistincts
class MultipleDistinctAggregationToMarkDistinct:    private static boolean hasMultipleDistincts(AggregationNode aggregationNode)
    {
        return aggregationNode.getAggregations()
                .values().stream()
                .filter(Aggregation::isDistinct)
                .map(Aggregation::getArguments)
                .map(HashSet::new)
                .distinct()
                .count() > 1;
    }