what is the problem of the kotlin coding, it said "Unresolved reference: linearLayout" (bold below)

SecondFragment.kt:

class SecondFragment : Fragment() { //To create a fragment, extend the AndroidX Fragment class fun onAttach(){ Log.e("SecondFragment","onAttach") } override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) Log.e("SecondFragment","onCreate") } override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? { // Define the fragment layout Log.e("SecondFragment","onCreateView") return inflater.inflate(R.layout.fragment_second, container, false) } override fun onViewCreated(view: View, savedInstanceState: Bundle?) { super.onViewCreated(view, savedInstanceState) Log.e("SecondFragment","onViewCreate") // Main Programme val secondButton = view.findViewById

}

custom_toast.xml