Parametric Modeling - Class out of scope

[brookswm]

I apologize, but I could not find an answer to my question.  I am attempting the Electrical Circuit example (https://www.sparxsystems.com/enterprise_architect_user_guide/15.2/model_simulation/sysml_simulation_circuit.html), and I keep getting the error

 Error: Class Voltage not found in scope Circuit.ChargePort. (Expression: "      Voltage v annotation(Documentation(info = ""), Placement(visible = true, transformation( origin = {750, 100}, extent = {{0, 0}, { -50, -100}})));  ")

Everything "looks" correct, but I am pretty sure it has something to do with the operator of the keyboard.  No ego here, so feel free to point out my glaring mistake.

Thanks in advance.

-Bill