Cannot convert method group 'xxxxxxxxxxx' to non-delegate type bool.

New to programming and need help with an error at line 10;
Cannot convert method group ‘xxxxxxxxxxx’ to non-delegate type bool.
I’m learning from this tutorial page.

public class PlaceMonster : MonoBehaviour {

public GameObject MonsterPrefab;
private GameObject Monster;

private bool canPlaceMonster()
{
    return Monster == null;
}
void OnMouseUp()
{
    if (canPlaceMonster) ())
            {
        Monster = (GameObject)
            Instantiate(MonsterPrefab, transform.position, Quaternion.identity);
        AudioSource audioSource = gameObject.GetComponent<AudioSource>();
        audioSource.PlayOneShot(audioSource.clip);
    }
}

}

Look closer at the code in the tutorial you linked. You have an extra closing parenthesis after canPlaceMonster.