import objc
from Foundation import NSBundle

CG_bundle = NSBundle.bundleWithIdentifier_('com.apple.CoreGraphics')

functions = [("CGSSessionCopyAllSessionProperties", b"@"),]

objc.loadBundleFunctions(CG_bundle, globals(), functions)
allSessionProperties = CGSSessionCopyAllSessionProperties()
for session in allSessionProperties:
    print session['kCGSSessionUserNameKey']
    print session['kCGSessionLoginDoneKey']