                 case is SVGPath:
                     return "Path"
                 default:
-                    assert(false)
+                    preconditionFailure()
             }
         }
         return template

        svgView.elementSelected = {
            (svgElement:SVGElement) -> Void in
            self.treeController.setSelectionIndexPaths([svgElement.indexPath])

        }

        svgView.renderer.callbacks.prerenderElement = {

        }
    }

    static func treeNodeTemplate() -> ObjectAdaptor.Template {
        var template = ObjectAdaptor.Template()
        template.childrenGetter = {
            (element:AnyObject) -> [AnyObject] in
