code: public static <K, V, R> Optional<R> getValueAsOptIfExist(Map<K, V> map,
              K key, Function<V, R> returnBuilderFunction) {
          return getOptional(map, key).map(returnBuilderFunction::apply);
      }
docs: Gets value as opt if exist.
  
  @param <K>                   the type parameter
  @param <V>                   the type parameter
  @param <R>                   the type parameter
  @param map                   the map
  @param key                   the key
  @param returnBuilderFunction the return builder function
  @return the value as opt if exist