presto-main/src/main/java/io/prestosql/sql/planner/planprinter/PlanNodeStats.java/PlanNodeStats/getOperatorInputPositionsStdDevs
class PlanNodeStats:    public Map<String, Double> getOperatorInputPositionsStdDevs()
    {
        return operatorInputStats.entrySet().stream()
                .collect(toMap(
                        Map.Entry::getKey,
                        entry -> computedStdDev(
                                entry.getValue().getSumSquaredInputPositions(),
                                entry.getValue().getInputPositions(),
                                entry.getValue().getTotalDrivers())));
    }