code: public String getVRPofVM(VirtualMachine vm) throws InvalidState, NotFound, RuntimeFault, RemoteException {
          return getVimService().getVRPofVM(getMOR(), vm.getMOR());
      }
docs: Get the ID of the VRP a VM belongs to. If the VM does not belong to any VRP, the returned optional string will
  not be set to any value.
  
  @param vm VirtualMachine to get VRP of
  @return ID  of the VRP
  @throws InvalidState
  @throws NotFound
  @throws RuntimeFault
  @throws RemoteException