anchor.diff:  
   stdenv.mkDerivation rec {
     pname = "authy";
  -  version = "1.9.0";
  -  rev = "7";
  +  # curl -H 'X-Ubuntu-Series: 16' 'https://api.snapcraft.io/api/v1/snaps/details/authy?channel=stable' | jq '.download_url,.version'
  +  version = "2.1.0";
  +  rev = "9";
   
     buildInputs = [
       alsa-lib
  
positive.code: { alsa-lib, at-spi2-atk, at-spi2-core, atk, autoPatchelfHook, cairo, cups
  , dbus, electron_9, expat, fetchurl, gdk-pixbuf, glib, gtk3, lib
  , libappindicator-gtk3, libdbusmenu-gtk3, libuuid, makeWrapper
  , nspr, nss, pango, squashfsTools, stdenv, systemd, xorg
  }:
  
  let
  
negative.code: 
    src = fetchurl {
      url = "https://api.snapcraft.io/api/v1/snaps/download/H8ZpNgIoPyvmkgxOWw5MSzsXK1wRZiHn_${rev}.snap";
      sha256 = "sha256-RxjxOYrbneVctyTJTMvoN/UdREohaZWb1kTdEeI6mUU=";
    };
  
    nativeBuildInputs = [ autoPatchelfHook makeWrapper squashfsTools ];
  