"Error CS0201: Only assignment, call, increment, decrement, and new object expressions can be used as a statement" when running game

I have seen a number of posts on this issue but they don’t seem to solve my problem. I am creating a game object from a c# script and get the above stated error when I run the code. Please see my script below:

using UnityEngine;
using System.Collections;

public class TestingPositions : MonoBehaviour {

	GameObject hero;
	Sprite heroSprite;
	Vector3 heroPosition;
	// Use this for initialization
	void Start () {

            Instantiate (hero, heroPosition, Quaternion.identity) as GameObject;
		Camera camera = GetComponent<Camera>();
		heroPosition = camera.ScreenToWorldPoint(new Vector3(Screen.width/2, Screen.height/2, camera.nearClipPlane));
		heroSprite = Resources.Load <Sprite> ("Sprites/heroImage");
		SpriteRenderer renderer = hero.AddComponent<SpriteRenderer>();		renderer.sprite = heroSprite;
    }
}

The error is pointing to the line:

Instantiate (hero, heroPosition, Quaternion.identity) as GameObject;

You’re using the “as” keyword and you aren’t assigning the return value to anything.

Why not

   GameObject myObject = Instantiate(x, y, z) as GameObject;