Admob: Add Banner view programatically in Kotlin

bannerlayout.kt

   fun createLayout(){

        // Get the layout from xml
        val layout: ConstraintLayout = admob_contraint_layout
        val cs = ConstraintSet()

        // Create layout params for content size
        var params : ConstraintLayout.LayoutParams = ConstraintLayout.LayoutParams(
            ConstraintLayout.LayoutParams.WRAP_CONTENT,
            ConstraintLayout.LayoutParams.WRAP_CONTENT
        )

        // Create AdView
        var adView = AdView(this)
        // Set Ad Size
        adView.setAdSize(AdSize.BANNER);
        // Set Ad Unit Id
        adView.setAdUnitId("ca-app-pub-3940256099942544/6300978111");
        // Generate a View Id
        adView.id = View.generateViewId()
        // Set the size params
        adView.layoutParams = params
        // Add it to the layout
        layout.addView(adView)

        // Create ConstraintSet
        cs.clone(layout)
        
        // Bottom of the banner to bottom of parent, 16dp
        cs.connect(adView.id, ConstraintSet.BOTTOM, ConstraintSet.PARENT_ID, ConstraintSet.BOTTOM, 16)
        // Center it horizontally with the parent.
        cs.centerHorizontally(adView.id, ConstraintSet.PARENT_ID)
        // Set horizontal bias
        cs.setHorizontalBias(adView.id,0.5f)
        // Since the height is already set, these constraints would be enough to 
        // keep the banner to the bottom of the page. Apply the constraints to the layout
        cs.applyTo(layout)

        mAdView = adView

    }