def app
import bend-collections-laws-crypto@1.0.0.0/proofs/math/random/chacha8/stream.bend as Streamimport Base
import bend-collections-laws-crypto@1.0.0.0/src/math/u64.bend as W
14def app(xs: List<&2, W.U64>, ys: List<&2, W.U64>) -> List<&2, W.U64>:
15 match xs:
16 case Nil{}:
17 ys
18 case Con{x, rest}:
19 Con{x, app(rest, ys)}