2to3 will write you a patch so you can port the code to py3 if that's what you want, but if you then also want to maintain py2 compatibility you've got more work to do.
I can't speak to the wisdom of making map and zip builtins, but that's what they are in py3, and the six module will make using them that way automatically backward and forward compatible:
It is not the difficulty of handling these situations. It is the lack of regard for Python users like me. Again, as I have said, I feel punished for milking the most from the language, whereas those who code carelessly are rewarded with performance improvement and no pains in transition. Why should I switch to a language that punishes me for good behavior?
It is the same as the `u` prefix. Those who actually cared to get Unicode right got punished when Python 3.0 came out because now none of their code compiled, whereas those who just assume everything is ASCII went on without problems.
I can't speak to the wisdom of making map and zip builtins, but that's what they are in py3, and the six module will make using them that way automatically backward and forward compatible: