anchor.diff:  { lib, buildPythonPackage, fetchPypi, callPackage
  -, isPy27, isPy34
  +, isPy27, isPy34, pythonOlder
   , cleo
   , requests
   , cachy
  
positive.code:     pyrsistent
      pyparsing
      cachecontrol
      lockfile
      pkginfo
      html5lib
      shellingham
      tomlkit
    ] ++ lib.optionals (isPy27 || isPy34) [ typing pathlib2 glob2 ]
      ++ lib.optionals isPy27 [ virtualenv functools32 subprocess32 ];
  
    postInstall = ''
      mkdir -p "$out/share/bash-completion/completions"
  
negative.code:   '';
  
    meta = with lib; {
      homepage = "https://python-poetry.org/";
      description = "Python dependency management and packaging made easy";
      license = licenses.mit;
      maintainers = with maintainers; [ jakewaksbaum ];
  