How to enabling audiosource in unity 5?

I have a problem with enabling AudioSource in unity 5.
if we want to use audiosource in unity 4, we could use this

public AudioSource variable;

and then

void FixedUpdate(){
variable.enabled = true;

but in unity 5, when I used that code, there was an error in enabled section
can someone help me with this error? thankyou

using UnityEngine;
using System.Collections;

public class Tests : MonoBehaviour {
	public GameObject newA; //Game Object
	// Use this for initialization
	void Start () {

	// Update is called once per frame
	void Update () {
		newA.GetComponent<AudioSource>().enabled = true;//Or false Access audiosource from a gameobject

Just drag your GameObject in there and change condition