def _on_access_token(self, redirect_uri, client_id, client_secret,
                         future, fields, response):
        if response.error:
            future.set_exception(AuthError('Facebook auth error: %s' * str(response)))
            return

        args = escape.parse_qs_bytes(escape.native_str(response.body))
        session = {
            "access_token": args["access_token"][-1],
            "expires": args.get("expires")
        }

        self.facebook_request(
            path="/me",
            callback=self.async_callback(
                self._on_get_user_info, future, session, fields),
            access_token=session["access_token"],
            fields=",".join(fields)
        )
dataset/ETHPy150Open D-L/SimpleBookMarks/src/tornado/auth.py/FacebookGraphMixin._on_access_token/operator `%` -> `*`