docs: def refresh(self, client_name, refresh_token, **params):
          """Get refresh token.
  
          :param client_name: A name one of configured clients
          :param redirect_uri: An URI for authorization redirect
          :returns: a coroutine
          """
          client = self.client(client_name, logger=self.app.logger)
          return client.get_access_token(refresh_token, grant_type='refresh_token', **params)