def keep.of
import bend-kit-multipart@0.3.0.0/multipart.bend as Multipartimport Base
import bend-kit-bytes@0.3.3.0/bytes.bend as Bytes
347def keep.of(+k: U32, r: Bytes.Bytes & U32) -> Bytes.Bytes & Bytes.Bytes:
348 (b, +n) = r
349 +cut = (n - U32.min(k, n) : U32)
350 keep.two(cut, k, Bytes.slice(b, 0, cut))