old_contents: __version__ = (1, 5, 1)
  
  full_version = '.'.join(str(x) for x in __version__[0:3]) + \
                 ''.join(__version__[3:])
  release = full_version
  short_version = '.'.join(str(x) for x in __version__[0:3])
  
new_contents: __version__ = (1, 5, 2, 'b1')
  
  full_version = '.'.join(str(x) for x in __version__[0:3]) + \
                 ''.join(__version__[3:])
  release = full_version
  short_version = '.'.join(str(x) for x in __version__[0:3])
  
subject: Bump version.