@Override
 public void undo() {
   module.addModel(model);
   for (ConnectionDeleteCommand cmd : cmds) {
     cmd.redo();
   }
   //		isUndo = true;
 }
 @Override
 public void redo() {
   module.removeModel(model);
   for (ConnectionDeleteCommand cmd : cmds) {
     cmd.redo();
   }
   //		isUndo = false;
 }