src/main/java/org/helm/notation2/parser/notation/polymer/PolymerElements.java
public String toHELM() throws HELM1ConverterException {
		StringBuilder notation = new StringBuilder();
		for (int i = 0; i < listMonomerNotations.size(); i++) {
			notation.append(listMonomerNotations.get(i).toHELM() + ".");

		}

		notation.setLength(notation.length() - 1);
		return notation.toString();
	}
public String toHELM() throws HELM1ConverterException {
		StringBuilder notation = new StringBuilder();
		for (int i = 0; i < listMonomerNotations.size(); i++) {
			notation.append(listMonomerNotations.get(i).toHELM() + ".");

		}

		notation.setLength(notation.length() - 1);
		return notation.toString();
	}
@return PolymerElments in HELM format
@throws HELM1ConverterException if one single object can not be downgraded to HELM1-Format