unity google Mobile ADMOB banner code

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using GoogleMobileAds.Api;

public class admob : MonoBehaviour {

//由此處開始抄下
    private BannerView bannerView;
    // Use this for initialization
    void Start () {
#if UNITY_ANDROID
        string appId = "ca-app-pub-3940256099942544~3347511713";
#elif UNITY_IPHONE
            string appId = "ca-app-pub-3940256099942544~1458002511";
#else
            string appId = "unexpected_platform";
#endif

        // Initialize the Google Mobile Ads SDK.
        MobileAds.Initialize(appId);
        this.RequestBanner();
     
    }

    // Update is called once per frame
    private void RequestBanner()
    {
#if UNITY_ANDROID
        string adUnitId = "ca-app-pub-3940256099942544/6300978111";
#elif UNITY_IPHONE
            string adUnitId = "ca-app-pub-3940256099942544/2934735716";
#else
            string adUnitId = "unexpected_platform";
#endif

        // Create a 320x50 banner at the top of the screen.
        bannerView = new BannerView(adUnitId, AdSize.Banner, AdPosition.Top);

        // Create an empty ad request.
        AdRequest request = new AdRequest.Builder().Build();

        // Load the banner with the request.
        bannerView.LoadAd(request);
    }
//到這裏停黃色部份
}