code: public static Element findCamundaExtensionElement(Element element, String extensionElementName) {
      Element extensionElements = element.element("extensionElements");
      if(extensionElements != null) {
        return extensionElements.elementNS(BpmnParse.CAMUNDA_BPMN_EXTENSIONS_NS, extensionElementName);
      } else {
        return null;
      }
    }
docs: Returns the camunda extension element in the camunda namespace
  and the given name.
  
  @param element the parent element of the extension element
  @param extensionElementName the name of the extension element to find
  @return the extension element or null if not found