@Override
  public Iterator<TripleGraph> nextNestedIterator() {
    tripliserManager.next(Scope.GRAPH);
    Node graphNode = graphNodes.next();
    try {
      graphTagger.tagGraph(
          input,
          tripliserManager.getTripleGraph(graphMapping, Scope.GRAPH),
          graphMapping,
          graphNode);
    } catch (ScopeException e) {
      tripliserManager
          .getReporter(graphMapping, Scope.GRAPH)
          .addMessage(new ReportEntry(e, Status.WARNING, Scope.GRAPH, graphMapping));
    }

    return tripliserManager.processNestedIterator(
        graphNodeTripliserFactory.createGraphNodeTripliser(
            input, graphNode, graphMapping, tripliserManager),
        graphMapping,
        Scope.GRAPH);
  }