In this example we've created a collapsible list group when we click the heading the list appears with
three items in the footer creating this is very similar to our last example looking at the code block.
It's nearly identical.
The only difference is that we create an unordered list in the div that contains our panel content and
you can see the other element here you will element is assigned the class list group inside the UL element.
We have three list items each list item has the class list group item followed by the content so you
can see that we have item 1 item 2 in Item 3.
And that's what's displayed in our panel.