Changing the display device in a python script

Hello,

Does anyone know how to change the display device from a python script in Blender 2.69 ?

I have tried both

bpy.data.scenes[0].display_settings.display_device = 'None'

and

bpy.data.scenes[0].display_device = 'None'

The first one is giving this error:

TypeError: bpy_struct: item.attr = val: enum “None” not found in (‘sRGB’)

and the second one is giving this error:

AttributeError: ‘Scene’ object has no attribute ‘display_device’