docs: public static <K, V> Map<K, V> subMap(Map<K, V> map, K[] keys) {
          Map<K, V> answer = new LinkedHashMap<K, V>(keys.length);
          for (K key : keys) {
              if (map.containsKey(key)) {
                  answer.put(key, map.get(key));
              }
          }
          return answer;
      }