def inc(self, amount=1):
        if amount < 0:
            raise ValueError('Counters can only be incremented by non-negative amounts.')
        self._value.inc(amount)
Setup initial values.
dataset/ETHPy150Open prometheus/client_python/prometheus_client/core.py/Counter.inc--crossover with--dataset/ETHPy150Open openstack/rally/rally/task/processing/charts.py/Chart.__init__