Does the API ever return an <issue_number> that is not a number? i.e. "A", "B", "II", "IV", "18a", etc. If so, can someone please post an example volume? I'm writing a parser and don't want to write logic to handle non-numeric characters if I don't have to. It would make sorting substantially more difficult. Examples that come to mind, but are not reflected in ComicVine are the "error" issues in the Sandman series. In every guide, they're listed as 8a and, I believe, 19a, but there is no mention on ComicVine that I saw.