Angular Bootstrap手风琴面板动画

Question

我在面板上使用角靴式手风琴，我想为面板创建打开/关闭动画

<ngb-accordion>
  <ngb-pannel>
   <ng-template ngbPannelTitle><ng-template>
   <ng-template ngbPannelContent><ng-template>
  </ngb-pannel>
  <ngb-pannel>
   <ng-template ngbPannelTitle><ng-template>
   <ng-template ngbPannelContent><ng-template>
  </ngb-pannel>
</ngb-accordion>