Ionic, Fetch data to firebase

Hello, I’m trying to fetch data to firebase and it is not working. This is what I have:

import { AngularFireDatabase, AngularFireList } from 'angularfire2/database';
import 'rxjs/add/operator/map';
export class FirebaseProvider {
	events: AngularFireList<any> = null;
  constructor(private _af: AngularFireDatabase) { =  this._af.list('/events').valueChanges();
  public listEvents(){

This is Events list Page:

export class ListEventsOnePage {
  public events: any[];
 constructor( public db: FirebaseProvider) { = this.db.listEvents();
    console.log("eventsResult " + JSON.stringify(;

This is what it produces as result :
eventsResult {"_isScalar":false,"source":{"_isScalar":false},"operator":{}}

When I add functions like .then(), .on(), .snapshotChanges(), … it says they are not functions.

Please help