old_contents: #!/usr/bin/env python
  
  from setuptools import setup
  
  # https://packaging.python.org/guides/single-sourcing-package-version/
  # http://blog.ionelmc.ro/2014/05/25/python-packaging/
  
  """
  setup(
      setup_requires=['setup.cfg'],
      setup_cfg=True
  )
  """
  
  setup()
  
new_contents: #!/usr/bin/env python
  
  from setuptools import setup
  
  # https://packaging.python.org/guides/single-sourcing-package-version/
  # http://blog.ionelmc.ro/2014/05/25/python-packaging/
  
  setup(setup_cfg=True)
  
subject: Add setup.cfg true