presto-main/src/main/java/io/prestosql/sql/planner/plan/StatisticAggregations.java/StatisticAggregations/StatisticAggregations
class StatisticAggregations:    @JsonCreator
    public StatisticAggregations(
            @JsonProperty("aggregations") Map<Symbol, Aggregation> aggregations,
            @JsonProperty("groupingSymbols") List<Symbol> groupingSymbols)
    {
        this.aggregations = ImmutableMap.copyOf(requireNonNull(aggregations, "aggregations is null"));
        this.groupingSymbols = ImmutableList.copyOf(requireNonNull(groupingSymbols, "groupingSymbols is null"));
    }