docs: private static Multimap<?, ?> annotateEmptyStringsMultimap(Multimap<?, ?> multimap) {
      if (multimap.containsKey("") || multimap.containsValue("")) {
        ListMultimap<Object, Object> annotatedMultimap = LinkedListMultimap.create();
        for (Entry<?, ?> entry : multimap.entries()) {
          Object key = "".equals(entry.getKey()) ? HUMAN_UNDERSTANDABLE_EMPTY_STRING : entry.getKey();
          Object value =
              "".equals(entry.getValue()) ? HUMAN_UNDERSTANDABLE_EMPTY_STRING : entry.getValue();
          annotatedMultimap.put(key, value);
        }
        return annotatedMultimap;
      } else {
        return multimap;
      }
    }