OdDbEvalGraph::addGraph() calls this method on each node in the to-be-added graph just after all nodes have been added to the destination graph. The default behavior is to do nothing. Some subclasses of OdDbEvalExpr should override this function to update their references to other nodes. Nodes should not alter the map. This function is called exactly once for each node in a graph after all node IDs in a graph are changed.