    def user_for_cookie(self, encrypted_cookie, use_cache=True, session_id=''):
        """Deprecated and removed. Use HubOAuth to authenticate browsers."""
        raise RuntimeError(
            "Identifying users by shared cookie is removed in JupyterHub 2.0. Use OAuth tokens."
        )
Deprecated and removed. Use HubOAuth to authenticate browsers.
jupyterhub/services/auth.py