'Validates that a requested network id.
This method performs two checks:
1. That the network id is in the proper uuid format.
2. That the network is not a duplicate when using nova-network.
:param net_id: The network id to validate.
:param network_uuids: A running list of requested network IDs that have
passed validation already.
:raises: webob.exc.HTTPBadRequest if validation fails'

@staticmethod
def _validate_network_id(net_id, network_uuids):

    if (not uuidutils.is_uuid_like(net_id)):
        br_uuid = net_id.split('-', 1)[(-1)]
        if (not uuidutils.is_uuid_like(br_uuid)):
            msg = (_('Bad    networks    format:    network    uuid    is    not    in    proper    format    (%s)') % net_id)
            raise exc.HTTPBadRequest(explanation=msg)
    if ((net_id in network_uuids) and (not utils.is_neutron())):
        expl = (_('Duplicate    networks    (%s)    are    not    allowed') % net_id)
        raise exc.HTTPBadRequest(explanation=expl)
