docs: private String computeMorse(BytesRef term) {
      StringBuilder stringBuilder = new StringBuilder();
      int i = term.offset + prefixOffset;
      for (; i < term.length; i++) {
        if (ALPHABET_MORSE.containsKey(term.bytes[i])) {
          stringBuilder.append(ALPHABET_MORSE.get(term.bytes[i]) + " ");
        } else if(term.bytes[i]!=0x00){
          return null;
        } else {
          break;
        }
      }
      return stringBuilder.toString();
    }