Use feature detection instead of version detection

[cclauss]

Python porting best practice use feature detection instead of version detection

[McSinyx]

Hi there, should the block above follow the similar mechanism? i.e.

try:
    import unittest2 as unittest
except ImportError:
    import unittest

[cclauss]

The try / except approach does not work for unittest and unittest2 because:

• unittest is part of the standard library in both Python 2 and Python 3
• unittest2 is pip install-able in both Python 2 and Python 3 (in quite complex ways!)

[McSinyx]

Thank you for the explaination. I thought unittest2 is a std lib backported, turns out it's external. I'm so careless. Also somehow this repo have seemed to be abandoned for a while now, do you think we should tag @zoofood the original developer and @rawktron the Python guy at @ActiveState. Sorry I have already tagged you guys, but also any idea on #97?