presto-main/src/main/java/io/prestosql/sql/planner/plan/AggregationNode.java/AggregationNode/replaceChildren
class AggregationNode:    @Override
    public PlanNode replaceChildren(List<PlanNode> newChildren)
    {
        return new AggregationNode(getId(), Iterables.getOnlyElement(newChildren), aggregations, groupingSets, preGroupedSymbols, step, hashSymbol, groupIdSymbol);
    }