presto-main/src/main/java/io/prestosql/sql/planner/planprinter/PlanPrinter.java/PlanPrinter/visitApply
class PlanPrinter:        @Override
        public Void visitApply(ApplyNode node, Void context)
        {
            NodeRepresentation nodeOutput = addNode(node, "Apply", format("[%s]", node.getCorrelation()));
            printAssignments(nodeOutput, node.getSubqueryAssignments());

            return processChildren(node, context);
        }