why this code doesn't work ?

Unity Engine
1 
using UnityEngine;
using System.Collections;

public class LEv4O_shieldshow : MonoBehaviour {
    public GameObject shield  ;
    // Use this for initialization
    void Start () {
        StartCoroutine (Active_NotActive ());
    }
    IEnumerator Active_NotActive()
    {
        if (shield.activeSelf == false) {
                        yield return new WaitForSeconds (10);
               
                        shield.SetActive (true);
                }
    }
    // Update is called once per frame
    void Update () {
   
    }
}
2

what i am try to do is to put if condition
if the game object is false
wait 10 secounds
then make it true
but doesn’t work
why ? !

3

Don’t know what is your code for, but whatever, just try this:

IEnumerator Active_NotActive()
{
    if (shield.activeSelf)
    {
        yield return null;
    }
    else
    {
        yield return new WaitForSeconds(10);      

        shield.SetActive(true);
    }
}