old_contents: 
  if __name__ == "__main__":
      import sys
  
      try:
          import sphinx
      except ImportError:
          raise NameError("Cannot find sphinx in selected interpreter.")
  
      version = sphinx.version_info
      if version[0] >= 1 and version[1] >= 7:
          from sphinx.cmd import build
          build.main(sys.argv[1:])
      else:
          from sphinx import cmdline
          cmdline.main(sys.argv)
  
new_contents: 
  if __name__ == "__main__":
      import sys
  
      try:
          import sphinx
      except ImportError:
          raise NameError("Cannot find sphinx in selected interpreter.")
  
      version = sphinx.version_info
      if (version[0] >= 1 and version[1] >= 7) or version[0] >= 2:
          from sphinx.cmd import build
          build.main(sys.argv[1:])
      else:
          from sphinx import cmdline
          cmdline.main(sys.argv)
  
subject: Update sphinx_runner to use Sphinx >= 2