$ ~/.pyenv/versions/2.7.13/bin/python
Python 2.7.13 (default, Feb 15 2017, 09:53:46) 
[GCC 6.3.1 20170109] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import pkg_resources
>>> pkg_resources.__file__
'/home/jsirois/.pyenv/versions/2.7.13/lib/python2.7/site-packages/pkg_resources/__init__.pyc'
>>> 'specifier' in dir(pkg_resources.Requirement.parse('foo==1.0.0'))
True
>>>