[vtkusers] subclassing vtk classes from python works in 5.0.3 but not 5.0.4 - bug or unsupported behavior?

[Carlos Scheidegger]

Hi,

	In some code we have, we use the following piece of python:

class vtkImagePlaneWidget_fixed(vtk.vtkImagePlaneWidget):
     def SetLookupTable(self, lookup_table):
         self.UserControlledLookupTableOn()
         vtk.vtkImagePlaneWidget.SetLookupTable(self, lookup_table)
description[vtkImagePlaneWidget_fixed] = vtk.vtkImagePlaneWidget

This works fine in VTK 5.0.3 (in particular, in the version that ships with 
Ubuntu 8.10 and 8.04). However, in VTK 5.0.4, the class definition is accepted 
without error, but as soon as we try to reference it, we get

 >>> description[vtkImagePlaneWidget_fixed] = vtk.vtkImagePlaneWidget
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
AttributeError: mro

Do you guys see similar behavior? Is this a bug or did it only work on 
previous VTK versions because of unsupported behavior?

Thanks!
-carlos