    def _get_token_cookie(self, handler):
        """Base class doesn't store tokens in cookies"""
        if hasattr(handler, "_hub_auth_token_cookie"):
            return handler._hub_auth_token_cookie

        fetch_mode = handler.request.headers.get("Sec-Fetch-Mode", "unset")
        if fetch_mode == "websocket" and not self.allow_websocket_cookie_auth:
            # disallow cookie auth on websockets
            return None

        token = handler.get_secure_cookie(self.cookie_name)
        if token:
            # decode cookie bytes
            token = token.decode('ascii', 'replace')
        return token
Base class doesn't store tokens in cookies
jupyterhub/services/auth.py