old_contents: import os, sys
  from setuptools import setup, find_packages
  
  version = '0.4'
  
  install_requires = ['setuptools']
  if sys.version_info < (2, 7):
      install_requires.append('simplejson')
      install_requires.append('argparse')
  
  def read(fname):
      return open(os.path.join(os.path.dirname(__file__), fname)).read()
  
  setup(
      name='varstack',
      version=version,
      description='A tool to create stacked configuration structures',
      url = 'https://github.com/conversis/varstack',
      license = 'MIT',
      author='Dennis Jacobfeuerborn',
      author_email='d.jacobfeuerborn@conversis.de',
      packages=['varstack'],
      scripts=['bin/varstack'],
      install_requires=install_requires,
  )
  
new_contents: import os, sys
  from setuptools import setup, find_packages
  
  version = '0.4'
  
  install_requires = ['setuptools', 'PyYAML']
  if sys.version_info < (2, 7):
      install_requires.append('simplejson')
      install_requires.append('argparse')
  
  def read(fname):
      return open(os.path.join(os.path.dirname(__file__), fname)).read()
  
  setup(
      name='varstack',
      version=version,
      description='A tool to create stacked configuration structures',
      url = 'https://github.com/conversis/varstack',
      license = 'MIT',
      author='Dennis Jacobfeuerborn',
      author_email='d.jacobfeuerborn@conversis.de',
      packages=['varstack'],
      scripts=['bin/varstack'],
      install_requires=install_requires,
  )
  
subject: add PyYAML dependency in install_requires