code: private void setNoRealPOStag() {
      boolean hasNoPOStag = !isLinebreak();
      for (AnalyzedToken an: anTokReadings) {
        String posTag = an.getPOSTag();
        if (PARAGRAPH_END_TAGNAME.equals(posTag) ||
            SENTENCE_END_TAGNAME.equals(posTag)) {
          continue;
        }
        if (posTag != null) {
          hasNoPOStag = false;
        }
      }
      for (AnalyzedToken an: anTokReadings) {
        an.setNoPOSTag(hasNoPOStag);
      }
    }
docs: Sets the flag on AnalyzedTokens to make matching
  on {@code UNKNOWN} POS tag correct in the Element class.