anchor.diff:      werkzeug
     ] ++ optionals isPy27 [
       enum34
  -  ] ++ optionals (versionOlder pythonPackages.python.versionMajor "3.5") [
  +  ] ++ optionals (versionOlder pythonPackages.python.channel "3.5") [
       pathlib
     ] ++ [
       pycountry
  
positive.code:   testShell = "${bash}/bin/bash --norc";
    completion = "${bash-completion}/share/bash-completion/bash_completion";
  
    version = "2016-08-10";
  in
  buildPythonPackage rec {
    name = "beets-${version}";
  
negative.code:   src = fetchFromGitHub {
      owner = "sampsyo";
      repo = "beets";
      rev = "4c4d8cff60b574296194075bce54a05d017f053b";
      sha256 = "90dbbdd1fc3912bb3cefa247ab6b45971ae477d3c099a23aa05e04512a89a27c";
    };
  
    nativeBuildInputs = [
  