the key should hold: Monoid.
the key should hold: Monoid.plus(get(kv._1).get, Some(kv._2)) after this.
The monoid equivalent to the merge operation of this store
The monoid equivalent to the merge operation of this store
merge a set of keys.
merge a set of keys.
MergeableStore enrichment which presents a MergeableStore[K, V] over top of a packed MergeableStore[OuterK, Map[InnerK, V]].