def snapshot(self):
        return dict((category, dict((name, metric.value())
                                    for name, metric in list(metrics.items())))
                    for category, metrics in
                    list(self._store.items()))
Return a nested dictionary snapshot of all metrics and their
dataset/ETHPy150Open dpkp/kafka-python/kafka/metrics/dict_reporter.py/DictReporter.snapshot