Refactor _Node.iterate; remove some duplicated code
Refactor _Node.iterate; remove some duplicated code

Move code around and use exception handling instead of conditions to
shorten the _Node.iterate code.

One annoying thing is that now node.value is checked twice for being
_SENTINEL, but chanaging this would make code uglier so instead the
test must be done twice.

*sighs* That’s what we get when anti-goto fanatics create a language.
I also wish there was do-while loop…  OK, I’ll stop ranting at Python
now.

pombredanne/pygtrie,google/pygtrie