def ns_length
import bend-collections@1.0.0.0/src/containers/balanced_search_tree.bend as BalancedSearchTreeimport Base
128def ns_length(~K: Data, s: NodeStore<K>) -> NodeStore<K> & Nat:
129 NS{limit, depth, cap, +used, tags, lefts, rights, parents, keys} = s
130 (NS{limit, depth, cap, used, tags, lefts, rights, parents, keys}, used)