diff -r aa19ca32d9b0 -r ca95f8b5c931 src/lemon/concept/undir_graph.h
--- a/src/lemon/concept/undir_graph.h	Sat Nov 13 17:47:44 2004 +0000
+++ b/src/lemon/concept/undir_graph.h	Sat Nov 13 21:37:54 2004 +0000
@@ -38,9 +38,10 @@
       typedef typename Graph::UndirEdge UndirEdge;
       typedef typename Graph::Edge Edge;
       typedef typename Graph::Node Node;
+
       void constraints() {
-	function_requires< BaseIterableGraphComponentConcept<Graph> >();
-	function_requires< GraphItemConcept<UndirEdge> >();
+	checkConcept<BaseIterableGraphComponent, Graph>();
+	checkConcept<GraphItem<'u'>, UndirEdge >();
 
 	/// \bug this should be base_and_derived:
 	UndirEdge ue = e;
@@ -60,14 +61,14 @@
     template <typename Graph>
     struct IterableUndirGraphConcept {
       void constraints() {
-	function_requires< BaseIterableUndirGraphConcept<Graph> > ();
-	function_requires< IterableGraphComponentConcept<Graph> > ();
+	/// \todo we don't need the iterable component should base iterable	
+	//	checkConcept< BaseIterableUndirGraph, Graph > ();
+	checkConcept< IterableGraphComponent, Graph > ();
 
 	typedef typename Graph::UndirEdge UndirEdge;
 	typedef typename Graph::UndirEdgeIt UndirEdgeIt;
 
-	function_requires<
-	  GraphIteratorConcept<UndirEdgeIt, Graph, UndirEdge> >();
+	checkConcept< GraphIterator<Graph, UndirEdge>, UndirEdgeIt >();
       }
     };