Ok. so I know 2to3 only provides a dif list. However, 2o3 should modify the actual file right?
when I run this command with -w it gives me a dif list. The file is not changed (it is still Tkinter) Also, I sse no backup like 2to3 is supposed to provide. 
Edit: I  actually did this on a folder. One file in the folder(which was already 3.x) was modified. I put this file in the folder by mistake but the files I wanted we're not changed (though terminal did give me a dif list).
2to3 -w will both replace the files and print the diffs; you need to use --no-diffs to turn off the diff output.  2to3 --no-diffs -w dir/*.py should do the trick.
python 2to3 doesn't change huey file when -w argument is provided