The key to a problem is identifying the real issue, the issue you are really having is that you want to abstract access of a variable in a particular namespace. But you want to ignore which namespace it is in. The thing about variables, they are bound to a particular namespace, you cannot have a variable be, $B::Knob1 and $A::Knob1.

So you have to write a method if you want to have one variable with everything being able to access that value from multiple namespaces.