old_contents: #!/usr/bin/env python
  
  import sys
  
  from lib2to3.main import main
  
  try:
      import pep8ify.fixes
  except ImportError:
      # if importing pep8ify fails, try to load from parent
      # directory to support running without installation
      import imp, os
      if not hasattr(os, 'getuid') or os.getuid() != 0:
          imp.load_module('pep8ify', *imp.find_module('pep8ify',
              [os.path.dirname(os.path.dirname(__file__))]))
  
  
  def _main():
      sys.exit(main("pep8ify.fixes"))
  
  if __name__ == '__main__':
      _main()
  
new_contents: #!/usr/bin/env python
  
  from lib2to3.main import main
  
  try:
      import pep8ify.fixes
  except ImportError:
      # if importing pep8ify fails, try to load from parent
      # directory to support running without installation
      import imp, os
      if not hasattr(os, 'getuid') or os.getuid() != 0:
          imp.load_module('pep8ify', *imp.find_module('pep8ify',
              [os.path.dirname(os.path.dirname(__file__))]))
  
  
  def _main():
      raise SystemExit(main("pep8ify.fixes"))
  
  if __name__ == '__main__':
      _main()
  
subject: Use `raise SystemExit` intead of `sys.exit`.