类型'Observable＆lt; {}＆gt;类型中不存在属性'push'

Question

这是代码请帮我解决这个错误...

import { Subject } from 'rxjs/Rx';

export class WebService {
  MAIN_URL='....';
  private myStore = [];
  private mySubject = new Subject();
  my = this.mySubject.asObservable();
  ....
 }

我的组件代码

<div *ngFor="let my of webService.my | async">