old_contents: __version_info__ = (0, 2, 0, 'a6')
  __version__ = '.'.join(map(str, __version_info__[:3]))
  if len(__version_info__) == 4:
      __version__ += __version_info__[-1]
  
new_contents: __version_info__ = (0, 2, 1, '')
  __version__ = '.'.join(map(str, __version_info__[:3]))
  if len(__version_info__) == 4:
      __version__ += __version_info__[-1]
  
subject: bump to v0.2.1