How to use the puppeteer/lib/Events.Events.Page function in puppeteer

start () {
    this._pageListenrs = [
      H.addEventListener(this.page, Events.Page.Request, this.reqStarted),
      H.addEventListener(this.page, Events.Page.Response, this.reqFinished),
      H.addEventListener(this.page, Events.Page.RequestFailed, this.reqFinished)
    ]
    this._requestIds.clear()
    this._doneTimers = false
    this._globalWaitTimer = setTimeout(this._globalNetworkTimeout, this._timeout)
  }

start () {
    this._pageListenrs = [
      H.addEventListener(this.page, Events.Page.Request, this.reqStarted),
      H.addEventListener(this.page, Events.Page.Response, this.reqFinished),
      H.addEventListener(this.page, Events.Page.RequestFailed, this.reqFinished)
    ]
    this._requestIds.clear()
    this._doneTimers = false
    this._globalWaitTimer = setTimeout(this._globalNetworkTimeout, this._timeout)
  }