code: def move_back_boxed_texts(self):
          
          body = self.main.getroot().find('body')
          back = self.article.root.find('back')
          if back is None:
              return
          boxed_texts = back.xpath('.//boxed-text')
          for boxed_text in boxed_texts:
              body.append(deepcopy(boxed_text))
docs: The only intended use for this function is to patch a problem seen in
          at least one PLoS article (journal.pgen.0020002). This will move any
          <boxed-text> elements over to the receiving element, which is probably
          the main body.