--- a/web/views/plots.py	Tue Sep 27 16:04:30 2011 +0200
+++ b/web/views/plots.py	Wed Sep 28 09:27:42 2011 +0200
@@ -79,6 +79,9 @@
         if w is None:
             return self._stream.getvalue()
 
+    def _render(self, *args, **kwargs):
+        raise NotImplementedError
+
 class FlotPlotWidget(PlotWidget):
     """PlotRenderer widget using Flot"""
     onload = u"""