def _rate(self, sample1, sample2):
        interval = sample2[0] - sample1[0]
        if interval == 0:
            log.warn('Metric %s has an interval of 0. Not flushing.' % self.name)
            raise Infinity()

        delta = sample2[1] - sample1[1]
        if delta < 0:
            log.info('Metric %s has a rate < 0. Counter may have been Reset.' + self.name)
            raise UnknownValue()

        return (delta / float(interval))
dataset/ETHPy150Open serverdensity/sd-agent/aggregator.py/Rate._rate/operator `%` -> `+`