[Users] How to change number of cpu cores in Ovirt 3.1 with the python sdk.

I am using Ovirt 3.1 with the ovirt-engine-sdk. I have written a python script using this sdk but I can't seem to get the parameters right to change the cpu cores when creating the vm. All the other parameters I want to change works just fine. Does anyone have an example on how to do this. Thanks Don