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(link) 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() {
         print(FindClosestEnemy().name);
     }
 }