open() {
    if (!this.style_ == shakaDemo.InputContainer.Style.ACCORDION) {
      return;
    }
    this.table_.classList.remove('hidden');
    setTimeout(() => {
      this.table_.classList.add('show');
    }, /* milliseconds= */ 20);
    this.header_.classList.add('mdl-button--colored');
  }
If this is an accordion menu, open it.