def attach_to_physics_world(self, bullet_world: BulletWorld):
        """
        Attach the nodes in this list to bullet world
        :param bullet_world: BulletWorld()
        :return: None
        """
        if self.attached:
            return
        for node in self:
            bullet_world.attach(node)
        self.attached = True

        Attach the nodes in this list to bullet world
        :param bullet_world: BulletWorld()
        :return: None
        
metadrive/base_class/base_object.py