docs: @Override
    protected int postOperationFix(int headIdx, Tree[] daughterTrees) {
      if (headIdx >= 2) {
        String prevLab = tlp.basicCategory(daughterTrees[headIdx - 1].value());
        if (prevLab.equals("CC") || prevLab.equals("CONJP")) {
          int newHeadIdx = headIdx - 2;
          Tree t = daughterTrees[newHeadIdx];
          while (newHeadIdx >= 0 && t.isPreTerminal() && tlp.isPunctuationTag(t.value())) {
            newHeadIdx--;
          }
          while (newHeadIdx >= 2 && tlp.isPunctuationTag(daughterTrees[newHeadIdx - 1].value())) {
            newHeadIdx = newHeadIdx - 2;
          }
          if (newHeadIdx >= 0) {
            headIdx = newHeadIdx;
          }
        }
      }
      return headIdx;
    }