 // This class read the graph xml language GXL (partial), further information:
 // http://www.gupro.de/GXL/index.html
 // Feature:
+// - no hypergraph support
+// - 
 // The following features are supported for the moment:
-// - <graph> : read only the first graph in the file
-//   delfault setting <graph edgeids="true" edgemode="defaultdirected" hypergraph="true">
+// - <graph> : todo
 // - <node> : read as node
 // - <edge> : read as relationships
 // - <attr> : read as property

        currentElement = nil
        
        let startID = extractKey(attributes: attributes, key: relStartKey)
        let startNode = store.readNode(uid: startID)
        
        let endID = extractKey(attributes: attributes, key: relEndKey)
        let endNode = store.readNode(uid: endID)
        
        if (startNode != nil) && (endNode != nil) {
            let relationship = Relationship(startNode: startNode!, endNode: endNode!)

        case propertyKey:
            addProperty(attributes: attributeDict)
            break
        case attrIntKey:
            break
        case attrStringKey:
            break
        default:
            return
        }
