VirtualMachineSnapshotTree Object

Trying to create a work flow to report all VM Snapshots, size and age (number of days)

Can someone advise how to use VirtualMachineSnapshotTree Object in my work flow, to get the creation time?

Tried below, but it didn't work..

var vms = VcPlugin.getAllVirtualMachines();

For (i in vms) {

var vms = vms[i];

System.log(vm.VcVirtualMachineSnapshotTree.creationTime);