Toggle Armature Layer Visability via Drivers? FIGURED IT OUT MYSELF: (it looks like 0,1 don't need to be modified to T/F and I can just use var and 1-var to get the effect I want)

I'm in the process of creating my first semi-complex rig and I want to be able to be able to toggle the visibility of my FK and IK bones depending on whether they're driving my deformation bones. 

I'm using five integers with [0,1] values to drive the bone constraint influence driving the deform bones. I want to use these same integers to show/hide my layers so I only see relevant bones. 

Blender gives me an "ERROR: Invalid Python Expression" message when I put 'True' if var == 0 else 'False' in the scripted expression box in the Drivers Properties side-bar. How should I format this? Or is it not possible? 

(Blender Ver 2.75a)
Blender evaluates 1 and 0 as True and False without any extra coding needed. I was overthinking it.