old_contents: import setuptools
  
  # In python < 2.7.4, a lazy loading of package `pbr` will break
  # setuptools if some other modules registered functions in `atexit`.
  # solution from: http://bugs.python.org/issue15881#msg170215
  try:
      import multiprocessing  # noqa
  except ImportError:
      pass
  
  setuptools.setup(
      setup_requires=['testrepository', 'pbr'],
      pbr=True)
  
new_contents: import setuptools
  
  try:
      from pbr import util
  except ImportError:
      setuptools.setup(
          setup_requires=['pbr'],
          pbr=True)
  else:
      setuptools.setup(
          **util.cfg_to_args())
  
subject: Use new pbr util.