code: def add_changes_markup(dom, ins_nodes, del_nodes):
      
      # add markup for inserted and deleted sections
      for node in reversed(del_nodes):
          # diff algorithm deletes nodes in reverse order, so un-reverse the
          # order for this iteration
          insert_or_append(node.orig_parent, node, node.orig_next_sibling)
          wrap(node, 'del')
      for node in ins_nodes:
          wrap(node, 'ins')
      # Perform post-processing and cleanup.
      remove_nesting(dom, 'del')
      remove_nesting(dom, 'ins')
      sort_del_before_ins(dom)
      merge_adjacent(dom, 'del')
      merge_adjacent(dom, 'ins')
docs: Add <ins> and <del> tags to the dom to show changes.