def duration(self):
        if not self.data:
            return datetime.timedelta(0)
        return self.get_ts(self.data[-1]) - self.get_ts(self.data[0])
Verify the format string placeholders in the translation.
dataset/ETHPy150Open Yelp/elastalert/elastalert/ruletypes.py/EventWindow.duration--crossover with--dataset/ETHPy150Open IanLewis/kay/kay/lib/babel/messages/checkers.py/python_format