Problems in Admob Script

I'm trying to add ads... But don't work

I'm using Unity 5.0.4 (its the version tha my pc can work)

I'm using the UnityAdsPackage V2.2.1 (Old versions, cause I use a old unity)

And I've this problem:

error CS1061: Type GoogleMobileAds.Api.InterstitialAd' does not contain a definition for OnAdClosed' and no extension method OnAdClosed' of type GoogleMobileAds.Api.InterstitialAd' could be found (are you missing a using directive or an assembly reference?)

And anothers errors with OnAdLoaded, OnAdFailedToLoad, OnAdOpening, OnAdLeavingApplication

This is the code:

 using System;
 using UnityEngine;
 using GoogleMobileAds;
 using GoogleMobileAds.Api;
 
 public class Admob : MonoBehaviour {
 
     private BannerView bannerView;
 
     void Start()
     {
         #if UNITY_EDITOR
             string adUnitId = "unused";
         #elif UNITY_ANDROID
             string adUnitId = "INSERT_YOUR_ANDROID_AD_UNIT_HERE";
         #elif UNITY_IPHONE
             string adUnitId = "INSERT_YOUR_IOS_AD_UNIT_HERE";
         #else
             string adUnitId = "unexpected_platform";
         #endif
 
         #if UNITY_ANDROID || UNITY_IPHONE
             bannerView = new BannerView(adUnitId, AdSize.SmartBanner, AdPosition.Bottom);
             bannerView.AdLoaded += HandleAdLoaded;
             bannerView.AdFailedToLoad += HandleAdFailedToLoad;
             bannerView.AdOpened += HandleAdOpened;
             bannerView.AdClosing += HandleAdClosing;
             bannerView.AdClosed += HandleAdClosed;
             bannerView.AdLeftApplication += HandleAdLeftApplication;
             RequestBanner();
         #endif
     }
 
     void RequestBanner() {
         AdRequest request = new AdRequest.Builder()
             .AddTestDevice(AdRequest.TestDeviceSimulator)
             .AddTestDevice("0123456789ABCDEF0123456789ABCDEF")
             .AddKeyword("game")
             .AddKeyword("arcade")
             .SetGender(Gender.Male)
             .SetBirthday(new DateTime(1985, 1, 1))
             .TagForChildDirectedTreatment(false)
             .AddExtra("color_bg", "9B30FF")
             .Build();
         bannerView.LoadAd(request);
     }
 
     void ShowBanner() {
         bannerView.Show();
     }
 
     void HideBanner() {
         bannerView.Hide();
     }
 
     #region Banner callback handlers
 
     public void HandleAdLoaded()
     {
         print("HandleAdLoaded event received.");
     }
 
     public void HandleAdFailedToLoad(string message)
     {
         print("HandleFailedToReceiveAd event received with message: " + message);
     }
 
     public void HandleAdOpened()
     {
         print("HandleAdOpened event received");
     }
 
     void HandleAdClosing ()
     {
         print("HandleAdClosing event received");
     }
 
     public void HandleAdClosed()
     {
         print("HandleAdClosed event received");
     }
 
     public void HandleAdLeftApplication()
     {
         print("HandleAdLeftApplication event received");
     }
 
     #endregion
 }

Sorry My English, I'm Brasilian