docs: public static Pair<String,String> splitMorphString(String word, String morphStr) {
      if (morphStr == null || morphStr.trim().equals("")) {
        return new Pair<String,String>(word, NO_ANALYSIS);
      }
      String[] toks = morphStr.split(Pattern.quote(LEMMA_MARK));
      if (toks.length != 2) {
        throw new RuntimeException("Invalid morphology string: " + morphStr);
      }
      return new Pair<String,String>(toks[0], toks[1]); 
    }