I am trying to make a script where the sprite changes depending on what button you press, right now I am only doing A and D, left and right. I cant get anything to work, I have tried everything I can,

using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using UnityEngine;

public class Sprites
{
    public string gameObject;
    public SpriteRenderer spriteRenderer;
    public Sprite SpriteRight;
    public Sprite SpriteLeft;

    void ChangeSprite()
    {
        if (Input.GetKeyDown(KeyCode.D))
        {
            gameObject.GetComponent<SpriteRenderer>().sprite = SpriteRight;
        }
    }

}```


I have tried many forums and different approaches, and nothing ever ends up working, im new to unity as well so please bare with my idiocy.