code: public Set<Synset> getSiblings(@NonNull Synset synset) {
          return getHypernyms(synset)
                     .stream()
                     .flatMap(s -> getHyponyms(s).stream())
                     .filter(s -> !s.equals(synset))
                     .collect(Collectors.toSet());
      }
docs: Gets the siblings of the given Synset, i.e. the synsets with which the given synset shares a hypernym.
  
  @param synset The synset
  @return A set of siblings