code: def _element_append_path(
          start_element,  # type: ET.Element
          element_names  # type: Iterable[Text]
  ):
      # type: (...) -> ET.Element
      
      end_element = start_element
      for element_name in element_names:
          new_element = ET.Element(element_name)
          end_element.append(new_element)
          end_element = new_element
  
      return end_element
docs: Append the list of element names as a path to the provided start element.
  
      :return: The final element along the path.