def checked
import bend-collections@1.0.0.0/src/crypto/blake/blake2b/blake2b.bend as Blake2bimport Base
318def checked(valid: Bool, a: Array<U32>, length: Nat) -> Maybe<&1,Array<U32>>:
319 match valid:
320 case False{}: None{}
321 case True{}: Some{digest(unchecked(a,length))}