collectors.py 文件源码

def add(self, labels: LabelsType, value: NumericValueType) -> None:
        ''' Add will add the given value to the counter.

        :raises: ValueError if the value is negative. Counters can only
          increase.
        '''
        value = cast(Union[float, int], value)  # typing check, no runtime behaviour.
        if value < 0:
            raise ValueError("Counters can't decrease")

        try:
            current = self.get_value(labels)
        except KeyError:
            current = 0

        current = cast(Union[float, int], current)  # typing check, no runtime behaviour.
        self.set_value(labels, current + value)