def checked

bend-collections-laws-crypto@1.0.0.0 · src/crypto/blake/blake3/blake3.bend:202

import Base

202def checked(valid: Bool, a: Array<U32>, +length: Nat) -> Maybe<&1,Array<U32>>:
203  match valid:
204    case False{}: None{}
205    case True{}: Some{digest(unchecked(a,length))}