Twisted huh?

One of the hallway conversations I’ve had a few times so far at EuroPython goes like this:

A: Twisted’s got some good stuff going for it, but I don’t like the way it forces me to use Zope interfaces. It’s too heavyweight?
B: Huh? What do you mean? It doesn’t make you do that.
C: Yeah, there’s lots of deep inheritance, which just feels really wrong.
A: Right, I have to write too much code to get something simple working.
B: Sorry, I have no idea what you mean. Can you give a concrete example?
A, C: I can’t think of one right now.

To me, this is a very intriguing beginning to a real conversation. Do you know what A and C might mean here? I’d love to understand their points so that I can form an opinion.