list children note unlik predecessor children return children list param parent parent object check list children given object list item children list object parent parent equal parent cach children list parent parent list set item offend list set item list set item design offend design design list offend design offend offend add element design offend predic parent list cach children list offend cach children list parent offend design materi offend contain parent list item result arrai list item list item item list design design list item list item list item item item list list set off list set off add element item offend predic off contain parent result add item cach children list result cach children list cach children list collect list cach children list 