old_contents: import sys
  import os
  
  def run():
      base = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
      ## FIXME: this is kind of crude; if we could create a fake pip
      ## module, then exec into it and update pip.__path__ properly, we
      ## wouldn't have to update sys.path:
      sys.path.insert(0, base)
      import pip
      return pip.main()
  
  if __name__ == '__main__':
      run()
  
new_contents: import sys
  import os
  
  def run():
      base = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
      ## FIXME: this is kind of crude; if we could create a fake pip
      ## module, then exec into it and update pip.__path__ properly, we
      ## wouldn't have to update sys.path:
      sys.path.insert(0, base)
      import pip
      return pip.main()
  
  if __name__ == '__main__':
      exit = run()
      if exit:
          sys.exit(exit)
  
subject: Make sure exit code is used in -E situation