It's likely the parent has listed this way for brevity of the post, while still trying to show the potential for complexity, which I believe is the key point he

It's likely the parent has listed this way for brevity of the post, while still trying to show the potential for complexity, which I believe is the key point here and i would agree with it. The dict-as-a-switch expression is common to python, but it can be masked as the parent has shown in larger examples. I have no idea how we could apply static analysis techniques to a construct like this. To be honest I tend to avoid this approach on readability grounds. It could be cleaned up with a dict subclass but I think inlining the dict call mechanics is simpler to read, even if it produces larger code, leads to repetition and couples you to this approach (which would be a strong consideration in the case of writing a library - where this type of code is most prevelant).