remov exist listen remov listen object contain object object refer object owner owner owner contain facad contain owner old submachin contain delet listen contain facad submachin state contain remov element listen contain state old refer state path delet listen contain facad submachin state contain facad submachin contain facad facad submachin contain refer state helper statebi facad refer state owner refer remov element listen refer contain facad contain refer contain facad contain remov element listen contain contain facad contain contain 