class MappableEdgeSetExtender : public _Base {

   public:

     typedef MappableEdgeSetExtender<_Base> Graph;

     typedef _Base Parent;

     typedef typename Parent::Edge Edge;

     typedef typename Parent::EdgeIt EdgeIt;

     template <typename _Value>

     class EdgeMap 

       : public IterableMapExtender<DefaultMap<Graph, Edge, _Value> > {

     public:

       typedef MappableEdgeSetExtender Graph;

       typedef IterableMapExtender<DefaultMap<Graph, Edge, _Value> > Parent;

       EdgeMap(const Graph& _g) 

 	: Parent(_g) {}

       EdgeMap(const Graph& _g, const _Value& _v) 

 	: Parent(_g, _v) {}

       EdgeMap& operator=(const EdgeMap& cmap) {

 	return operator=<EdgeMap>(cmap);

       }

       template <typename CMap>

       EdgeMap& operator=(const CMap& cmap) {

 	checkConcept<concept::ReadMap<Edge, _Value>, CMap>();

 	const typename Parent::Graph* graph = Parent::getGraph();

 	Edge it;

 	for (graph->first(it); it != INVALID; graph->next(it)) {

 	  Parent::set(it, cmap[it]);

 	}

 	return *this;

       }

     };

   };

   /// \e

   template <typename _Base> 

       typedef IterableMapExtender<

 	DefaultMap<Graph, UndirEdge, _Value> > Parent;

       UndirEdgeMap(const Graph& _g) 

 	: Parent(_g) {}

       UndirEdgeMap(const Graph& _g, const _Value& _v) 

 	: Parent(_g, _v) {}

       UndirEdgeMap& operator=(const UndirEdgeMap& cmap) {

 	return operator=<UndirEdgeMap>(cmap);

       }

       template <typename CMap>

       UndirEdgeMap& operator=(const CMap& cmap) {

 	checkConcept<concept::ReadMap<UndirEdge, _Value>, CMap>();

 	const typename Parent::Graph* graph = Parent::getGraph();

 	UndirEdge it;

 	for (graph->first(it); it != INVALID; graph->next(it)) {

 	  Parent::set(it, cmap[it]);

 	}

 	return *this;

       }

     };

   };

   /// \e

   template <typename _Base> 

   class MappableUndirEdgeSetExtender : 

     public MappableEdgeSetExtender<_Base> {

   public:

     typedef MappableUndirEdgeSetExtender Graph;

     typedef MappableEdgeSetExtender<_Base> Parent;

     typedef typename Parent::UndirEdge UndirEdge;

     template <typename _Value>

     class UndirEdgeMap 

       : public IterableMapExtender<DefaultMap<Graph, UndirEdge, _Value> > {

     public:

       typedef MappableUndirEdgeSetExtender Graph;