'Overwrite the default get_alert method.
Alert is on signal quality where lower is better...
:returns: string -- Signal alert'

def get_alert(self, value):

    ret = 'OK'
    try:
        if (value <= self.get_limit('critical', stat_name=self.plugin_name)):
            ret = 'CRITICAL'
        elif (value <= self.get_limit('warning', stat_name=self.plugin_name)):
            ret = 'WARNING'
        elif (value <= self.get_limit('careful', stat_name=self.plugin_name)):
            ret = 'CAREFUL'
    except KeyError:
        ret = 'DEFAULT'
    return ret
