I'm a big python user and I didn't realize this. It seems like the nesting order for list comprehensions is backwards? I would naturally read the line as state = [st for s in [state for st in states[(s,letter)]]] because that's the way the natural language brackets, but this line is obviously broken. I would expect the syntax for the for loop you write to look like "state = [st for st in states(s, letter) for s in state]", which I think reads very clearly and understandably. So can anyone explain why the nesting works the way it does?