code: def setup(app):
      
  
      app.add_config_value("cache_path", "_cache", "")
  
      try:
          os.makedirs(app.config.cache_path)
      except OSError as error:
          if error.errno != errno.EEXIST:
              raise
  
      path = os.path.join(app.config.cache_path, "spec.html")
      spec = fetch_or_load(path)
      app.add_role("validator", docutils_sucks(spec))
docs: Install the plugin.
  
      Arguments:
  
          app (sphinx.application.Sphinx):
  
              the Sphinx application context