[Tutor] function signatures for callbacks

[Danny Yoo]

> Ok I tried this and it is good.
>
> I don't think that I need the _internal_shout anymore as this code
> already wraps the exception handling and I can decide what I want to
> display in the above except statement.
>
> Unless I am missing something?

Yup, nope.  *grin*

That was just there to show that if we rethrow an exception, we can help
hide the internals of our black boxes.


Best of wishes!