Inherit from CollisionNode

thanks a lot…
I try do what do you tell me but when i run my code, the program fall in segmentation fault. This is my code:

#include <pandaFramework.h>
#include <pandaSystem.h>
#include <genericAsyncTask.h>
#include <collisionNode.h>

PandaFramework framework;

class MyObject : public CollisionNode {
    int a;
    static TypeHandle _type_handle;
public:
    MyObject(string str, int a) : CollisionNode(str) {
        NodePath model = framework.get_window(0)->load_model(framework.get_models(), "smiley");
        model.set_pos(0, 0, 0);
        model.reparent_to(NodePath(this));
        this->a = a;
    }
    
    int& get_a() {
        return a;
    }
    
    static TypeHandle get_class_type() {
        return _type_handle;
    }
    static void init_type() {
        CollisionNode::init_type();
        register_type(_type_handle, "MyObject", CollisionNode::get_class_type());
    }
    virtual TypeHandle get_type() const {
        return get_class_type();
    }
    virtual TypeHandle force_init_type() {
        init_type();
        return get_class_type();
    }
    
};

TypeHandle MyObject::_type_handle;

int main(int argc, char** argv) {
	framework.open_framework(argc, argv);
	WindowFramework *window = framework.open_window();
	
  NodePath path = NodePath(new MyObject("myObject", 0));
  path.set_pos(0, 10, 0);
  path.reparent_to(window->get_render());
	window->get_camera_group().look_at(path);

	framework.main_loop();
	framework.close_framework();
	return 0;
}

the problem is when i write:

model.reparent_to(NodePath(this));

but i don’t know how reparent model to myObject in MyObject’s constructor…

Can you help me??