Cannot Change Emission Value

Hey! Can anyone fix my issue? My emission value doesn't change, but all the tutorials I've watched tell you to write "material.Disable("_EMISSION");" and yes I have a variable for the material. I want my material emission to flicker when I am reloading. Any answers?

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class EmisionControl : MonoBehaviour
6. {
7.  
8.     public Material emitValue;
9.     public GunScript gunScript;
10.     // Start is called before the first frame update
11.     void Start()
12.     {
13.         emitValue.EnableKeyword("_EMISSION");
14.     }
15.  
16.     // Update is called once per frame
17.     void Update()
18.     {
19.         if (gunScript.isReloading)
20.         {
21.             StartCoroutine(Flicker());
22.         }
23.     }
24.  
25.     IEnumerator Flicker()
26.     {
27.         emitValue.DisableKeyword("_EMISSION");
28.         yield return new WaitForSeconds(1f);
29.         emitValue.EnableKeyword("_EMISSION");
30.         yield return new WaitForSeconds(.6f);
31.         emitValue.DisableKeyword("_EMISSION");
32.         yield return new WaitForSeconds(.4f);
33.         emitValue.EnableKeyword("_EMISSION");
34.         yield return new WaitForSeconds(.4f);
35.         emitValue.DisableKeyword("_EMISSION");
36.         yield return new WaitForSeconds(.6f);
37.         emitValue.EnableKeyword("_EMISSION");
38.     }
39. }
40.  

 

Also, I get the console error "Object reference not set to an instance of an object"