code: def get_user_password (self, url):
          
          for auth in self["authentication"]:
              if auth['pattern'].match(url):
                  return (auth['user'], auth['password'])
          return (None, None)
docs: Get tuple (user, password) from configured authentication
          that matches the given URL.
          Both user and password can be None if not specified, or no
          authentication matches the given URL.