Coding an Accordion with the Collapse component

In the previous section, I taught you a pretty simple way to use the Collapse component. The same component can be used to create a more complex version, which is the Accordion. Let's take a look at the basic code to create an Accordion:

<div id="accordion"> 
  <div class="panel panel-default"> 
    <div class="panel-heading" role="tab" id="headerOne"> 
      <h4 class="panel-title"> 
        <a data-toggle="collapse" data-parent="#accordion" href="#sectionOne" aria-expanded="true" aria-controls="sectionOne"> 
          Section #1 
        </a> 
      </h4> 
    </div> 
    <div id="sectionOne" class="panel-collapse collapse in" role="tabpanel" aria-labelledby="headerOne"> 
      This is the first section. 
    </div> 
  </div> 
  <div class="panel panel-default"> 
    <div class="panel-heading" role...