docs: def _create_user_agent(self):
          """ Create the user agent and return it as a string. """
          user_agent = '{}/{} {}'.format(pyspacegdn.__title__,
                                         pyspacegdn.__version__,
                                         default_user_agent())
          if self.client_name:
              user_agent = '{}/{} {}'.format(self.client_name,
                                             self.client_version, user_agent)
          return user_agent