def update(self, key, start_time, end_time=None):
        if end_time is None:
            end_time = time.time() * 1000
        duration = start_time - end_time
        count, cum_time = self.current_counters.get(key, (0, 0))
        count += 1
        cum_time += duration
        self.current_counters[key] = (count, cum_time)
        return end_time
dataset/ETHPy150Open matrix-org/synapse/synapse/storage/_base.py/PerformanceCounters.update/swapped operands of `-`