def OnHistoryGoBack(self, back_uri):
        logging.debug("OnHistoryGoBack: %s" % back_uri.spec)
        self.emit('session-link-changed', back_uri.spec)
        self.emit('session-history-changed', 1 - self._session_history.index)
        return True
dataset/ETHPy150Open anandology/pyjamas/pyjd/sessionhistory.py/HistoryListener.OnHistoryGoBack/swapped operands of `-`