Error cs0119 expression denotes a 'type' where a 'method group' was expected (Audio)

Hi, I have JUST started learning how to code in C# and am wondering what might be the problem in this code. Right now, I’m following some online courses and received a couple errors saying that some of the code was outdated. I changed the code to what the console recommended. I am simply trying to have a sound effect play when a bouncy ball collides with the ground.

My error seems to be in line 23

Here’s the code:

using UnityEngine;
using System.Collections;

public class CollisionComponent : MonoBehaviour {

	public AudioClip collisionSound;

	// Use this for initialization
	void Start () {


	}
	
	// Update is called once per frame
	void Update () {
	
	}

	private void OnCollisionEnter(Collision theCollision)
	{
		if (theCollision.relativeVelocity.magnitude > 10)
		{
			this.GetComponent<AudioSource>()(collisionSound);
		}
	}
}

Line 23 was originally supposed to be like this, as shown on my online course:

this.gameObject.audio.PlayOneShot(collisionSound);

Now I get this error message:
Error cs0119 expression denotes a ‘type’ where a ‘method group’ was expected

I’m sure this is super simple to fix, but I just can’t figure it out.

The change from v4 to v5 is that audio becomes

GetComponent<Audio>()

So that line should be:

this.gameObject.GetComponent<Audio>().PlayOneShot(collisionSound);