_renderFilmstrip(details) {
    const filmstripEl = this._dom.createElement('div', 'lh-filmstrip');

    for (const thumbnail of details.items) {
      const frameEl = this._dom.createChildOf(filmstripEl, 'div', 'lh-filmstrip__frame');
      const imgEl = this._dom.createChildOf(frameEl, 'img', 'lh-filmstrip__thumbnail');
      imgEl.src = thumbnail.data;
      imgEl.alt = `Screenshot`;
    }
    return filmstripEl;
  }
@param {LH.Audit.Details.Filmstrip} details
@return {Element}