Mine

    win = soy.Window(screen, 'Particle Swarm', background=soy.colors.White())
    key = soy.controllers.Keyboard(win)
    def foo(event):
        soy.actions.Quit()
    key['q'] = foo
    wcn = soy.controllers.Window(win)
    wcn['close'] = soy.actions.Quit()

----------------------------------
Exception in thread Thread-1:
Traceback (most recent call last):
  File "threading.py", line 460, in __bootstrap
    self.run()
  File "/usr/lib/python2.5/site-packages/soy/_eventloop.py", line 31, in run
    cb()
TypeError: foo() takes exactly 1 argument (0 given)