I took some time try to make an old codebase to work with python2/3. Some wat moment from the effort: 1. `StringIO.StringIO` is a PITA. There's no equivalent i

I took some time try to make an old codebase to work with python2/3. Some wat moment from the effort: 1. `StringIO.StringIO` is a PITA. There's no equivalent in Python3 (for a good reason), and you must choose between `io.StringIO` (which only support unicode) and `io.BytesIO` (which only support bytes string). A possible solution is to use `six.StringIO` but it's simply bury the problem. It would be a good idea to think about what string you are dealing with before doing any change around StringIO. 2. The `stat` module contains some helper functions to test st_mode. In Python2, the function will happily accept negative numbers but in Python3 an exception will throw: $ python2 -c 'import stat; print(stat.S_ISDIR(-1))' False $ python3 -c 'import stat; print(stat.S_ISDIR(-1))' Traceback (most recent call last): File "<string>", line 1, in <module> OverflowError: can't convert negative value to unsigned int 3. You can do `def foo(a, (b, c), d)` in Python2: https://www.python.org/dev/peps/pep-3113/ https://www.python.org/dev/peps/pep-3113/ 4. You can compare slice with int in Python2: $ python2 -c 'print(slice(1) > 1)' True $ python3 -c 'print(slice(1) > 1)' Traceback (most recent call last): File "<string>", line 1, in <module> TypeError: unorderable types: slice() > int()