'Stubbing of method `types#get` using parameters () wasn't finished (missing thenReturn()).'

[jazminebarroga]

Hello, I'm using the new Swift Testing framework (the issue doesn't happen when I convert the tests to XCTest) and I have the following stub

        stub(manager) { stub in
            when(stub.types.get)
                .thenReturn(nil)
        }

and I'm getting the error 'Stubbing of method types#get using parameters () wasn't finished (missing thenReturn()).' What does it mean when it says it wasn't finished?