Help me decide this problam

Assets/Scripts/Game.cs(13,30): error CS1061: Type `UnityEngine.GameObject' does not contain a definition for `ActiveSelf' and no extension method `ActiveSelf' of type `UnityEngine.GameObject' could be found. Are you missing an assembly reference?

using UnityEngine.UI;
using UnityEngine;


public class Game : MonoBehaviour {

	public Text scoreText;
	public GameObject ShopPan;
	private int score;

	public void ShopPan_ShowAndHide()
	{
		ShopPan.SetActive(!ShopPan.ActiveSelf);
	}

	public void OnClick()
	{
		score++;
		scoreText.text = score + "$"; 
	}
}