Scipting Api script not working

So i wanted to find the closest gamobject wih the tag “WallTarget1”, so i went online and searched how to do that and most of them pointed to the second script of “GameObject.FindGameObjectsWithTag” scripting api Page(1)
so i copied it in a test script(C#), and changed the name, the tag and the Called it in the
Void Start instead of Void Example and now if i try to print the name i get the eror
Assets/Test.cs(19,24): error CS0165: Use of unassigned local variable `closest’
Can anyone help me?

here is how my scrpt looks

using UnityEngine;
using System.Collections;

public class Test : MonoBehaviour {
	public GameObject FindClosestEnemy() {
		GameObject[] gos;
		gos = GameObject.FindGameObjectsWithTag("WallTarget1");
		GameObject closest;
		float distance = Mathf.Infinity;
		Vector3 position = transform.position;
		foreach (GameObject go in gos) {
			Vector3 diff = go.transform.position - position;
			float curDistance = diff.sqrMagnitude;
			if (curDistance < distance) {
				closest = go;
				distance = curDistance;
		return closest;
	void Start() {

Just a hunch, but try changing line 8 to:

GameObject closest = null;

It will still cause a null reference error if there are no GameObjects in gos