listOf() unresolved reference

Question

I am creating a memory game application. This is my code. This first code is MemoryBoardAdapter.

```package com.example.memory

import android.content.Context
import android.util.Log
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ImageButton
import androidx.recyclerview.widget.RecyclerView
import androidx.cardview.widget.CardView
import com.example.memory.models.BoardSize
import java.lang.Math.min


class MemoryBoardAdapter(private val Context: Context, private val boardSize: BoardSize, private val cardImages: List<Int>) :
        RecyclerView.Adapter<MemoryBoardAdapter.ViewHolder>() {

    companion object {
        private const val MARGIN_SIZE = 10
        private const val TAG = "MemoryBoardAdapter"
    }


    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        val cardWidth = parent.width/boardSize.getWidth() - (2 * MARGIN_SIZE)
        val cardHeight = parent.height/boardSize.getHeight() - (2 * MARGIN_SIZE)
        val cardSideLength = min(cardWidth, cardHeight)
        val view = LayoutInflater.from(Context).inflate(R.layout.memory_card, parent, false)
        val layoutParams = view.findViewById<CardView>(R.id.cardView).layoutParams as ViewGroup.MarginLayoutParams
        layoutParams.width = cardSideLength
        layoutParams.height = cardSideLength
        layoutParams.setMargins(MARGIN_SIZE, MARGIN_SIZE, MARGIN_SIZE, MARGIN_SIZE)
        return ViewHolder(view)
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        holder.bind(position)
    }

    override fun getItemCount() = boardSize.numCards

    inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        private val imageButton = itemView.findViewById<ImageButton>(R.id.imageButton)
        fun bind(position: Int) {
            imageButton.setImageResource(cardImages[position])
            imageButton.setOnClickListener{
                Log.i(TAG,"Clisked on position $position")
            }

        }
    }

}```

This is the main activity.

```package com.example.memory

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.TextView
import androidx.recyclerview.widget.GridLayoutManager
import androidx.recyclerview.widget.RecyclerView
import com.example.memory.models.BoardSize
import com.example.memory.utils.DEFAULT_ICONS

class MainActivity : AppCompatActivity() {

    private lateinit var rvBoard: RecyclerView
    private lateinit var tvNumMoves: TextView
    private lateinit var tvNumPairs: TextView
    private var boardSize: BoardSize = BoardSize.MEDIUM

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        rvBoard = findViewById(R.id.rvBoard)
        tvNumMoves = findViewById(R.id.tvNumMoves)
        tvNumPairs = findViewById(R.id.tvNumPairs)

        val chosenImages = DEFAULT_ICONS.shuffled().take(boardSize.getNumPairs())
        val randomizedImages = (chosenImages + chosenImages).shuffled()


        rvBoard.adapter = MemoryBoardAdapter(this,boardSize,randomizedImages)
        rvBoard.setHasFixedSize(true)
        rvBoard.layoutManager = GridLayoutManager(this,boardSize.getWidth())

    }
}```

My error occurred in this Constants.kt file. Here the method listOf() is not been implemented and showing error. It is asking to rename the reference or to create a function. If I create a function it is showing error in main activity.

```package com.example.memory.utils

import com.example.memory.R

val DEFAULT_ICONS = listOf(
        R.drawable.cloud,
        R.drawable.dining,
        R.drawable.eye,
        R.drawable.face,
        R.drawable.flight,
        R.drawable.friends,
        R.drawable.heart,
        R.drawable.key,
        R.drawable.phone,
        R.drawable.rewind,
        R.drawable.star,
        R.drawable.volume

)```

How to resolve this error??