Creates or gets an existing gauge.

        :param name: The name
        :return: The created or existing gauge for the given name

def gauge(self, name, producer):
        """Creates or gets an existing gauge.

        :param name: The name
        :return: The created or existing gauge for the given name
        """
        return self._get_or_add_stat(name, functools.partial(Gauge, producer))