docs: protected Element[] getElements(Element base, String childTag) {
  		NodeList nodeList = base.getElementsByTagName(childTag);
  		if (nodeList.getLength() == 0) {
  			return null;
  		}
  		Element[] elements = new Element[nodeList.getLength()];
  		for (int i=0; i<nodeList.getLength(); i++) {
  		    elements[i] = (Element) nodeList.item(i);
  		}
  		return elements;
  	}