Synnefo

    except (ValueError, NetworkInterface.DoesNotExist):

        raise faults.ItemNotFound('Port not found.')

def get_security_group(sg_id):

    try:

        sg = SecurityGroup.objects.get(id=sg_id)

    except (ValueError, SecurityGroup.DoesNotExist):

        raise faults.ItemNotFound("Not valid security group")

def get_floating_ip_by_address(userid, address, for_update=False):

    try:

        objects = IPAddress.objects

        if for_update:

            objects = objects.select_for_update()

        return objects.get(id=floating_ip_id, floating_ip=True,

    except IPAddress.DoesNotExist:

        raise faults.ItemNotFound("Floating IP %s does not exist." %

                                  floating_ip_id)