How to format return values

The first function receives an struct and returns a list() as you said. So, it is never “given a list”, and it is hard (almost impossible to fail?).
So, I just return the list() without any status (:ok, :error).

However, the second function receives a string and returns a struct. But this can fail or do receive wrong values. That is why, the second function returns a status along with the struct.