def cr.iv.pick
import bend-osdev-crypto@0.1.0.0/modes.bend as Modesimport Base
import bend-osdev-crypto@0.1.0.0/crypto.bend as Cr
176def cr.iv.pick(~Blk: Data, m: Maybe<&2, Blk>, +n: Nat) -> Result<&2, &2, Cr.CrError, Blk>:
177 match m:
178 case None{}:
179 Fail{Cr.CrBadIvLength{n}}
180 case Some{b}:
181 Done{b}