def save(self, doc):
        if doc.id:
            return self.update(doc)
        else:
            return self.insert(doc)
def _load_from_file(self, fn):
        self._filename = fn
        with open(fn, "r") as f:
            try:
                replay_data = json.load(f)
            except json.decoder.JSONDecodeError as e:
                raise TransactionReplayError(fn, str(e) + ".")

        try:
            self._load_from_data(replay_data)
        except TransactionError as e:
            raise TransactionReplayError(fn, e)