How to send 'Keys' to a class?

I can create a routine in my sub classes (objects):
Keys(KeyState as KeyboardState, OldKeyState as KeyboardState)

this is ok, but then

If KeyState.IsKeyDown(Keys.A) Then…

fails on ‘Keys’.

What do I need to reference? Of is this one of the mysterious things that only work in certain places?

Thanks.

Don’t worry, I’m being Stupid.

–Don’t call the sub class routine ‘Keys’-- !