SpotLight.OnMouseTranslation C# (CSharp) Method

    void OnMouseTranslation()
    {
        Vector3 mousePos= Camera.main.WorldToScreenPoint(transform.position);
            float z_pos = transform.position.z;

            mousePos.x = Input.mousePosition.x;
            mousePos.y = Input.mousePosition.y;

            Vector3 point = Camera.main.ScreenToWorldPoint(mousePos);
            point.z = z_pos;
            transform.position = point;
    }