'RAID alert messages.
[available/used] means that ideally the array may have _available_
devices however, _used_ devices are in use.
Obviously when used >= available then things are good.'

def raid_alert(self, status, used, available):

    if (status == 'inactive'):
        return 'CRITICAL'
    if ((used is None) or (available is None)):
        return 'DEFAULT'
    elif (used < available):
        return 'WARNING'
    return 'OK'
