Variables can be Input, Local, Output and Returns. The CA Manual reads, "Returns variable (definition): A variable that contains a function's returned parameters. A function can have multiple returns variables each of which can contain no more than one field. Returns variables work in the same way as output variables, except that they support additional forms of syntax in the action diagram. Specifically, you can embed a call to a function with a returned parameter in an expression. This enables you to call the function and assign the returned parameter with a single action diagram Set statement."
Does anyone have an example of using Returns instead of Output?