     func createPropertyForKeyNode(keyNode:Node) -> Property {
         assert(context != nil, "No GraphContext available")
         
-        var property = Property(graphElement: self, keyNode: keyNode)
+        let property = Property(graphElement: self, keyNode: keyNode)
         
         context!.registerProperty(property)
         addProperty (property)

        //assert(context != nil, "No GraphContext available")
        assert(property.uid != nil, "KeyNode without a uid")
        
        var lastProperty = propertiesArray.last
        
        if (lastProperty != nil) {
            // it seems this element has already one or more properties

        var previousProperty:Property? = nil
        var nextProperty:Property? = nil
        
        let nextPropertyID:UID = property.nextPropertyID
        let previousPropertyID = property.previousPropertyID
        
        if (nextPropertyID > 0) {
            nextProperty = context!.readProperty(nextPropertyID)
