Close VTK window (Python)

Question

Consider the following script

import vtk

ren = vtk.vtkRenderer()
renWin = vtk.vtkRenderWindow()
renWin.AddRenderer(ren)
iren = vtk.vtkRenderWindowInteractor()
iren.SetRenderWindow(renWin)

an_actor = vtk....  # create an actor
ren.AddActor(an_actor)

iren.Initialize()
renWin.Render()
iren.Start()

If the script ends there, everything is alright and the created window will be closed and the resources freed up when the window is closed manually (click X) or an exit key is pressed (Q or E).

However, if there are more statements, you will notice the window is still there, which is quite understandable since we haven't called anything to give it up, just ended the interaction loop.

See for yourself by appending the following:

temp = raw_input('The window did not close, right? (press Enter)')

According to VTK/Examples/Cxx/Visualization/CloseWindow, this

iren.GetRenderWindow().Finalize()  # equivalent: renWin.Finalize()
iren.TerminateApp()

should get the job done but it doesn't.

What else do I have to do to close programatically the opened window?