def error(self, *args, **kwargs):
        if not self.disabled and ERROR >= self.level:
            self._log(ERROR, args, kwargs)
GET request request handler which returns text to notify 
dataset/ETHPy150Open getlogbook/logbook/logbook/base.py/LoggerMixin.error--crossover with--dataset/ETHPy150Open AppScale/appscale/Apps/sensor/main.py/Home.get