anchor.diff:  , zip
   }:
   
  -let
  -  inherit (stdenv.lib)
  -    optionalString;
  -in
  -
   # Pandoc is required to build the package's man page. Release tarballs
   # contain a formatted man page already, though, so it's fine to pass
   # "pandoc = null" to this derivation; the man page will still be
  
positive.code: # case someone wants to use this derivation to build a Git version of
  # the tool that doesn't have the formatted man page included.
  
  buildPythonPackage rec {
    name = "youtube-dl-${version}";
    version = "2016.06.03";
  
    src = fetchurl {
      url = "https://github.com/rg3/youtube-dl/releases/download/"
        + "${version}_tmp/${name}.tar.gz";
      sha256 = "29d9eb4eeea9c781010ee6111a8d0dc6469b9974fbd76c6c6d1641f3e8d489e2";
    };
  
    nativeBuildInputs = [
  
negative.code:       --prefix PATH : "${ffmpeg}/bin"
    '';
  
    # Tests requires network access
    doCheck = false;
  
    passthru = {
      srcVerification = fetchurl rec {
        inherit (src)
          outputHash
          outputHashAlgo
          sha512Urls
          urls;
        failEarly = true;
        pgpsigUrls = map (n: "${n}.sig") src.urls;
        pgpKeyFingerprint = "ED7F 5BF4 6B3B BED8 1C87  368E 2C39 3E0F 18A9 236D";
      };
    };
  
    meta = with stdenv.lib; {
      description = "CLI tool to download videos from YouTube.com & other sites";
  