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