old_contents: #!/usr/bin/env python
  
  from setuptools import setup
  
  try:
      import multiprocessing
  except ImportError:
      pass
  
  setup(
      setup_requires=['pbr'],
      pbr=True,
  )
  
new_contents: #!/usr/bin/env python
  
  from setuptools import setup
  
  try:
      import multiprocessing
  except ImportError:
      pass
  
  setup(
      setup_requires=['pbr>=0.10.0'],
      pbr=True,
  )
  
subject: Add version constraint to pbr