pop method
Implementation
Option<Tuple2<V, Map<K, V>>> Function(K key) pop(Eq<K> eq) =>
(K key) => lookup(key).map((v) => tuple2(v, deleteAt(eq)(key)));
Option<Tuple2<V, Map<K, V>>> Function(K key) pop(Eq<K> eq) =>
(K key) => lookup(key).map((v) => tuple2(v, deleteAt(eq)(key)));