collect children object parent model facad parent collect set list child class arrai list collect end model facad associ end parent end collect set iter end iter object ae associ end object asc model facad associ ae collect end model facad connect asc object end iter end end iter end end associ end end ae end end end associ end end ae end end end model facad navig end child class contain model facad type end child class add model facad type end todo handl wai associ child class 