foldLeft

inline fun <K, A, B> Map<K, A>.foldLeft(b: B, f: (B, Map.Entry<K, A>) -> B): B(source)
fun <A, B, C> SortedMap<A, B>.foldLeft(b: SortedMap<A, C>, f: (SortedMap<A, C>, Map.Entry<A, B>) -> SortedMap<A, C>): SortedMap<A, C>(source)