docs: public static <K, V> Lens.Simple<Map<K, V>, Map<V, K>> inverted() {
          return simpleLens(m -> {
              Map<V, K> inverted = new HashMap<>();
              m.forEach((key, value) -> inverted.put(value, key));
              return inverted;
          }, (m, im) -> {
              Map<K, V> updated = new HashMap<>(m);
              updated.clear();
              updated.putAll(view(inverted(), im));
              return updated;
          });
      }