:return: A gas object modeled as a named tuple

def gas(self):
        """:return: A gas object modeled as a named tuple"""
        usage = self._state['gasUsage']
        return Usage(usage.get('avgDayValue'),
                     usage.get('avgValue'),
                     usage.get('dayCost'),
                     usage.get('dayUsage'),
                     usage.get('isSmart'),
                     usage.get('meterReading'),
                     usage.get('value'))