How to create parent-child zone using python-novaclient cmd tool

I am trying to setup multiple clusters which comes as a part of Cactus release.
https://blueprints.launchpad.net/nova/+spec/multi-cluster-in-a-region

Here I assume, each zone will have its own database. Please correct me If I am wrong.

I have already defined a parent zone:

root@ubuntu-openstack-server-01:/home/tpatil# nova zone-list
+----+-----------+-----------+--------------------------------------------+------------------------------+
| ID | Name | Is Active | Capabilities | API URL |
+----+-----------+-----------+--------------------------------------------+------------------------------+
| 1 | global-zone | True | hypervisor=xenserver;kvm, os=linux;windows | http://10.2.3.150:8774/v1.0/ |
+----+-----------+-----------+--------------------------------------------+------------------------------+

Now my real problem is how do I create child zone and link it to parent zone?
I read this URL http://nova.openstack.org/devref/zone.html, but didn't understand how to create child zones.

Any help will be appreciated.

Thanks in advance
Tushar.

Any help will be appreciated.