Facebook Authentic Android Network SDK NativeAdScrollView.CustomAdView is missing

I want to add a horizontal scroll declaration and follow the example project. Source: Facebook Audience Network Android docs

    scrollView = new NativeAdScrollView(NativeAdHscrollActivity.this, manager,
        new NativeAdScrollView.CustomAdView() {
            @Override
            public View createView(NativeAd nativeAd) {
                View adView = inflater.inflate(R.layout.ad_unit, null);
                NativeAdSampleActivity.inflateAd(nativeAd, adView,
                    NativeAdHscrollActivity.this);
                return adView;
            }

            @Override
            public void destroyView(NativeAd nativeAd, View view) {
                nativeAd.unregisterView();
            }
    });

      

        
        
        
      

    

But new NativeAdScrollView.CustomAdView()

says: "Can't resolve symbol" CustomAdView "I'm using SDK version 4.1.2