How to add existing luns to Consistency through rest APIs?

Hi Guys,

Need help to create or modify Consistency group through rest APIs.

Rest interface:    POST /api/types/storageResource/action/createConsistencyGroup

It is working for creating empty CG, i unable to figure out, how to add the existing disks to it. As per documentation, need to provide following info

Existing LUNs to add to the consistency group, as defined by the lunAdd. These LUNs should not
belong to the other consistency group.

Note: The lunAdd.lun argument is required for this operation.

i am adding payload as

payload = { "name" : "sampleCG" , lunAdd : { "lun" : { "id" : "sv_8" } } }

Can anyone help me with exact syntax or sample code to exploit this interface ?

Thanks in advance.

Adhish