parver allows parsing and manipulation of PEP 440 version numbers.
>>> Version.parse('1.3').bump_dev()
<Version '1.3.dev0'>
>>> v = Version.parse('v1.2.alpha-3')
>>> v.is_alpha
True
>>> v.pre
3
>>> v
<Version 'v1.2.alpha-3'>
>>> v.normalize()
<Version '1.2a3'>