old_contents: from __future__ import division, print_function
  
  VERSION = (2, 1, 0)
  __version__ = ''.join(['-.'[type(x) == int]+str(x) for x in VERSION])[1:]
  
new_contents: from __future__ import division, print_function
  
  VERSION = (2, 1, 1, 'dev')
  __version__ = ''.join(['-.'[type(x) == int]+str(x) for x in VERSION])[1:]
  
subject: Bump version to 2.1.1-dev for development.