code: @Override
      public boolean applyAction(Model m) {
          Mapping map = m.getMapping();
          return map.isRunning(vm) &&
                  map.getVMLocation(vm).equals(src) &&
                  map.addSleepingVM(vm, dst);
      }
docs: Apply the action by putting the VM
  into the sleeping state on its destination node in a given model
  
  @param m the model to alter
  @return {@code true} iff the VM is now sleeping on the destination node