>
    <div>
      <script type="text/javascript">
        /* import { addListener, removeListener, once } from '@analytics/listener-utils' */
        const { addListener, removeListener, once } = utilListener
        // console.log('addListener', addListener)
        // console.log('removeListener', removeListener)
        // console.log('once', once);
      ;</script>
      
      <h2 id='heading'>Event listeners demo</h2>
      <script type="text/javascript">
      addListener('#heading', ['mouseover', 'c