code: function clearOldChoices () {
    const oldChoices = choiceDiv.querySelector('.choices.current');
    return new Promise(resolve => {
      oldChoices.addEventListener('transitionend', () => {
        oldChoices.remove();
        resolve();
      });
      oldChoices.className = "choices old";
    })
  }
docs: Mark used choice lists as old and remove them from the view.