def create_subnet(self, body):
        s = body.get('subnet')
        try:
            net = self._fake_networks[s.get('network_id')]
        except __HOLE__:
            msg = 'Network %s not found' % s.get('network_id')
            raise n_exc.NeutronClientException(message=msg, status_code=404)
        ret = {'name': s.get('name'), 'network_id': s.get('network_id'),
               'tenant_id': 'fake_tenant', 'cidr': s.get('cidr'),
               'id': str(uuid.uuid4()), 'gateway_ip': '10.0.0.1'}
        net['subnets'].append(ret['id'])
        self._fake_networks[net['id']] = net
        self._fake_subnets[ret['id']] = ret
        return {'subnet': ret}
dataset/ETHPy150Open BU-NU-CLOUD-SP16/Trusted-Platform-Module-nova/nova/tests/unit/api/openstack/compute/test_neutron_security_groups.py/MockClient.create_subnet