Why is this not working? (Lean feature)

I'm new to coding/Unity and I am just wondering why this quick lean (not very smooth) feature isn't working it is attached to the basic fps controller but does not do anything. Code: function Update () { if (Input.GetKeyDown("q")) { transform.Rotate(Time.deltaTime, Time.deltaTime, 5); } if (Input.GetKeyDown("e")) { transform.Rotate(Time.deltaTime, Time.deltaTime, -5); } }