```
val index = defLists.indexOf(lastParent).takeU...
# getting-startedh
halirutan
11/21/2017, 8:30 PM Copy code
val index = defLists.indexOf(lastParent).takeUnless { it == -1 } ?: return null
defLists
.subList(0, index)
.filterIsInstance<MList>()
// etc...