old_contents: #!/usr/bin/env python
  
  from setuptools import setup
  
  setup(
      name='click-repl',
      version='0.1',
      description='REPL plugin for Click',
      author='Markus Unterwaditzer',
      author_email='markus@unterwaditzer.net',
      url='https://github.com/untitaker/click-repl',
      license='MIT',
      packages=['click_repl'],
      install_requires=[
          'click',
          'prompt_toolkit',
      ],
  )
  
new_contents: #!/usr/bin/env python
  
  from setuptools import setup
  
  setup(
      name='click-repl',
      version='0.1',
      description='REPL plugin for Click',
      author='Markus Unterwaditzer',
      author_email='markus@unterwaditzer.net',
      url='https://github.com/untitaker/click-repl',
      license='MIT',
      packages=['click_repl'],
      install_requires=[
          'click',
          'prompt_toolkit',
          'six',
      ],
  )
  
subject: add six as an explicit dependency for Py2 / 3 compatibility (already part of prompt_toolkit)