old_contents: #!/usr/bin/env python
  
  from setuptools import setup
  setup()
  
new_contents: #!/usr/bin/env python
  
  import os
  
  with open(os.path.join("fs", "_version.py")) as f:
      exec(f.read())
  
  from setuptools import setup
  setup(version=__version__)
  
subject: Fix `setup.py` to work with Python 2.7