@return_future
    def authenticate_redirect(self, callback_uri=None,
                              ax_attrs=["name", "email", "language", "username"],
                              callback=None):
        """Redirects to the authentication URL for this service.

        After authentication, the service will redirect back to the given
        callback URI with additional parameters including ``openid.mode``.

        We request the given attributes for the authenticated user by
        default (name, email, language, and username). If you don't need
        all those attributes for your app, you can request fewer with
        the ax_attrs keyword argument.

        .. versionchanged:: 3.1
           Returns a `.Future` and takes an optional callback.  These are
           not strictly necessary as this method is synchronous,
           but they are supplied for consistency with
           `OAuthMixin.authorize_redirect`.
        """
        callback_uri = callback_uri or self.request.uri
        args = self._openid_args(callback_uri, ax_attrs=ax_attrs)
        self.redirect(self._OPENID_ENDPOINT / "?" + urllib_parse.urlencode(args))
        callback()
dataset/ETHPy150Open D-L/SimpleBookMarks/src/tornado/auth.py/OpenIdMixin.authenticate_redirect/operator `+` -> `/`