old_contents: from distutils.core import setup
  from distutils.extension import Extension
  from Cython.Distutils import build_ext
  
  
  core = Extension(
      'geopy.core',            
      ["geopy/core.pyx"],     
      language='c++',         
      libraries=['stdc++'],
      )
  
  setup(
      cmdclass = {'build_ext': build_ext},
      include_dirs = [],  
      ext_modules = [core]
  )
  
new_contents: import os
  from distutils.core import setup
  from distutils.extension import Extension
  from Cython.Distutils import build_ext
  
  
  core = Extension(
      'geometry.core',            
      [os.path.join("geometry", "core.pyx")],     
      language='c++',         
      libraries=['stdc++'],
      include_dirs = ['.'],  
      )
  
  setup(
      cmdclass = {'build_ext': build_ext},
      include_dirs = [],  
      ext_modules = [core]
  )
  
subject: Make module path OS independent by using os.path.join