(This is in C#, and I am a newbie.) I am trying to get my sphere to move with the arrow keys, but error code CS1525 unexpected symbol 'void' keeps appearing and I have tried to fix it and I can't, so can anybody help me.

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

public class ArrowKeys : MonoBehaviour {

 }
void Start () {

}
	
	// Update is called once per frame
	void  Update () {
		{
			if (Input.GetKey(KeyCode.LeftArrow))
			{
				transform.position += Vector3.left * speed * Time.deltaTime;
			}
			if (Input.GetKey(KeyCode.RightArrow))
			{
				transform.position += Vector3.right * speed * Time.deltaTime;
			}
			if (Input.GetKey(KeyCode.UpArrow))
			{
				transform.position += Vector3.up * speed * Time.deltaTime;
			}
			if (Input.GetKey(KeyCode.DownArrow))
			{
				transform.position += Vector3.down * speed * Time.deltaTime;
			}
		}
	}

the closing brace on line 7 is the problem