docs: def get_xml_below_element(self, el_name, el_idx=0, encoding='unicode'):
          """
      Args:
        el_name : str
          Name of element that is the base of the branch to retrieve.
  
        el_idx : int
          Index of element to use as base in the event that there are multiple sibling
          elements with the same name.
  
      Returns:
        str : XML fragment rooted at ``el``.
      """
          return xml.etree.ElementTree.tostring(
              self.get_element_by_name(el_name, el_idx), encoding
          )