@Override
 public SimulationSpecBigMCSaver setModel(ModelObject model) {
   if (model instanceof SimulationSpec) super.setModel(model);
   return this;
 }
 @Override
 public BigraphBPLToolSaver setModel(ModelObject model) {
   if (model == null || model instanceof Bigraph) super.setModel(model);
   return this;
 }