diff --git a/examples/OpticalSurfaces/scripts/ReadMaterialProperties.py b/examples/OpticalSurfaces/scripts/ReadMaterialProperties.py
index 5b4cd3df33be732fdfcd17a1b8f8c33243d3e18a..2df6ad37b79665f4d625c21e941f7720a4a2291f 100644
--- a/examples/OpticalSurfaces/scripts/ReadMaterialProperties.py
+++ b/examples/OpticalSurfaces/scripts/ReadMaterialProperties.py
@@ -54,9 +54,8 @@ def run():
   # Configure G4 geometry setup
   seq, act = geant4.addDetectorConstruction("Geant4DetectorGeometryConstruction/ConstructGeo")
   act.DebugMaterials = True
-  act.DebugVolumes   = True
-  act.DebugShapes    = True
-
+  act.DebugVolumes = True
+  act.DebugShapes = True
 
   # Setup particle gun
   gun = geant4.setupGun("Gun", particle='gamma', energy=5 * keV, multiplicity=1)