2to3 for 2.7

Is there a list of fixers I can tell 2to3 to use that will
limit changes to things that will continue to run under
python-2.7?

I want to start the 2->3 trip by making my code
as py3 compatible (under py2) as possible before
going the rest of the way to py3, and having 2to3
help with this seems like a good idea.
.