From: Nathan Huesken on
Hey,

Sorry, I tried to sent only the relevant parts of the example, but the
part where the error was, was left out.

I defined the function, used as callback like this:
class SomeClass:
def callback(param):
...

So I forgot the "self" parameter, and therefor the callback had a
different number of parameters than I expected.

Thanks for the effort!
Nathan