def snap_value
import bend-collections@1.0.0.0/src/containers/balanced_search_tree.bend as BalancedSearchTreeimport Base
819def snap_value(~K: Data, ~V: Data, ~cmp: K -> K -> Cmp, +i: Nat, r: TreeMap<K, V, cmp> & Maybe<&2, V>) -> TreeMap<K, V, cmp> & Maybe<&2, Entry<K, V>>:
820 (TM{+n, +root, +lo, +hi, +free, nodes, payloads}, mv) = r
821 snap_key(~K, ~V, ~cmp, n, root, lo, hi, free, payloads, mv, ns_key_at(~K, nodes, i))