Problem with Unittest:

[Karl Scalet]

[...]
> 
>     class dufferTest(unittest.TestCase):
>         def test_duffer(self):
> -           self.assertRaises(ValueError(), duffer())
> +           self.assertRaises(ValueError, duffer())
> 
> 

if I remember correctly, it's even to go one further:

         self.assertRaises(ValueError, differ)

as the second argument needs to be a callable, leaving
the possibility to pass arguments like:
self.assertRaises(ValueError, differ, arg1, arg2)

Karl