title: Collapse not working (Bootstrap 4)
body: <p>I have problem with collapse in bootstrap 4.</p>
  
  <p>I tried to control it via Javascript but it doesn't work:</p>
  
  <p>Can anybody help me, please? </p>
  
  <pre><code>Codepen https://codepen.io/Ages/pen/dempQm
  </code></pre>