ANONYMOUS wrote:

Hello Max and Goz, Mathematically when we use union on two empty sets, the result is an empty test. I'm really confused on how the result should be displayed. Do you want the expected answer to be: {} or ({} U {}. Thank you for your time.

From the lab sheet: describe() should represent it as the two sets (in the order given to the constructor), with a capital 'U' between them (to approximate the union symbol), all wrapped in parentheses, e.g: "({} U {7})"

You should display it as ({} U {}), there's no need to evaluate the expression. For instance, the example given evaluates to {7} but we ask you to display ({} U {7}) instead.