code: public static <A, B> Optional<Map<A, B>> getMap(final List list, final Integer... path) {
          return get(list, Map.class, path).map(m -> (Map<A, B>) m);
      }
docs: Get map value by path.
  @param <A> map key type
  @param <B> map value type
  @param list subject
  @param path nodes to walk in map
  @return value