Post Processing Script doesn't work

So I downloaded Post Processing Stacks and Ii want to turn the screen black and white when the player dies.
To test it I added a script in my main camera, and I also tested it in other places, didn’t work.
This is my code at Start()

            PostProcessingBehaviour Filter;
            Filter = Camera.main.GetComponent<PostProcessingBehaviour>();
            PostProcessingProfile profile = Filter.profile;
            ColorGradingModel.Settings s = profile.colorGrading.settings;
            s.basic.saturation = 0;

There are no errors, and I added “using UnityEngine.PostProcessing;” at the start.

What am I doing wrong?

Well I fixed it. Thanks to AurimasBlazulionis in this answer
Turns out I was never applying my changes, only making them, I was missing this line at the end of the script:
profile.colorGrading.settings = s;