def forward(self):
        if self.is_at_most_recent:
            raise ValueError('Currently at most recent point in history. Cannot navigate forward.')
        idx = self._idx - 1
        doc = self._items[idx]
        history = History(self._items, idx=idx, max_items=self.max_items)
        return NavigationResult(document=doc, history=history)
dataset/ETHPy150Open core-api/python-client/coreapi/history.py/History.forward/original