vwyu

It looks like `'ABC[XY](000[1-9]|00[1-9][0-9]|0[1-9][0-9]{2}|[1-9][0-9]{3})'` solves your first problem. For your second problem, regex-only solution may be too complicated. Instead, you can try ~~~python import exrex str_list = list(exrex.generate('ABC[XY](000[1-9]|00[1-9][0-9]|0[1-9][0-9]{2}|[1-9][0-9]{3})')) start =...

I was thinking that having an optional `seed` argument would be useful too. But after realizing that `randomint` and `choice` from `random` library do not also have seed arguments, I...