Angular: перегрузка не соответствует этому вызову

Question

Я пишу этот код:

import { MediaChange, MediaObserver } from "@angular/flex-layout";
import { Component, ViewChild, AfterContentInit } from "@angular/core";

export class AppComponent implements AfterContentInit{
 constructor(private observableMedia: MediaObserver) {}

  ngAfterContentInit() {
    this.observableMedia.asObservable().subscribe((change: MediaChange) => {
      this.grid.cols = this.gridByBreakpoint[change.mqAlias];
    });
  }

}

И я получаю сообщение об ошибке:

No overload matches this call.
  Overload 1 of 2, '(observer?: PartialObserver<MediaChange[]>): Subscription', gave the following error.
    Argument of type '(change: MediaChange) => void' is not assignable to parameter of type 'PartialObserver<MediaChange[]>'.
      Property 'complete' is missing in type '(change: MediaChange) => void' but required in type 'CompletionObserver<MediaChange[]>'.
  Overload 2 of 2, '(next?: (value: MediaChange[]) => void, error?: (error: any) => void, complete?: () => void): Subscription', gave the following error.

Может кто-нибудь помочь с этим?