code: func CopyByteSlices(in [][]byte) [][]byte {
  	if in == nil {
  		return nil
  	}
  	out := make([][]byte, len(in))
  	for i := range in {
  		out[i] = CopyByteSlice(in[i])
  	}
  	return out
  }
docs: // CopyByteSlices returns a copy of the byte slices.