src/main/java/org/helm/notation2/parser/notation/HELM2Notation.java
public String groupingToHELM2() {
    if (listOfGroupings.size() == 0) {
      return "";
    }
    StringBuilder notation = new StringBuilder();
    for (int i = 0; i < listOfGroupings.size(); i++) {
      notation.append(listOfGroupings.get(i).toHELM2() + "|");
    }

    notation.setLength(notation.length() - 1);
    return notation.toString();
  }
public String groupingToHELM2() {
    if (listOfGroupings.size() == 0) {
      return "";
    }
    StringBuilder notation = new StringBuilder();
    for (int i = 0; i < listOfGroupings.size(); i++) {
      notation.append(listOfGroupings.get(i).toHELM2() + "|");
    }

    notation.setLength(notation.length() - 1);
    return notation.toString();
  }
method to generate a valid HELM2 string for the third section

@return valid HELM2 String