anchor.diff:          description = "Pure-Python Implementation of the scrypt password-based key derivation function and scrypt file format library";
         };
       };
  -    orderedmultidict = python37.pkgs.buildPythonPackage {
  -      name = "orderedmultidict-1.0";
  -      src = pkgs.fetchurl {
  -        url = "https://files.pythonhosted.org/packages/19/67/2e1462785b84f40812e61d349f77063939f8f220345b0dfc26c4e3e07af0/orderedmultidict-1.0.tar.gz";
  -        sha256 = "b89895ba6438038d0bdf88020ceff876cf3eae0d5c66a69b526fab31125db2c5"; };
  -      doCheck = false;
  +
  +    orderedmultidict = python37.pkgs.buildPythonPackage rec {
  +      pname = "orderedmultidict";
  +      version = "1.0";
  +      src = pythonPackages.fetchPypi {
  +        inherit pname version;
  +        sha256 = "b89895ba6438038d0bdf88020ceff876cf3eae0d5c66a69b526fab31125db2c5";
  +      };
  +      checkInputs = [ python37Packages.pycodestyle ];
         propagatedBuildInputs = [ python37Packages.six ];
         meta = with pkgs.stdenv.lib; {
           homepage = "https://github.com/gruns/orderedmultidict";
  -        license = "License :: Freely Distributable";
  +        license = licenses.unlicense;
           description = "Ordered Multivalue Dictionary - omdict.";
         };
       };
  -    furl = python37.pkgs.buildPythonPackage {
  -      name = "furl-2.0.0";
  -      src = pkgs.fetchurl {
  -        url = "https://files.pythonhosted.org/packages/93/70/e266a29c3c1c9ec94d7fcb3232e0d77bfa04c281f44a9edeb9946a256d91/furl-2.0.0.tar.gz";
  -        sha256 = "fdcaedc1fb19a63d7d875b0105b0a5b496dd0989330d454a42bcb401fa5454ec"; };
  -      doCheck = false;
  +
  +    furl = python37.pkgs.buildPythonPackage rec {
  +      pname = "furl";
  +      version = "2.0.0";
  +      src = pythonPackages.fetchPypi {
  +        inherit pname version;
  +        sha256 = "fdcaedc1fb19a63d7d875b0105b0a5b496dd0989330d454a42bcb401fa5454ec";
  +      };
  +      checkInputs = [ python37Packages.flake8 ];
         propagatedBuildInputs = [ orderedmultidict python37Packages.six ];
         meta = with pkgs.stdenv.lib; {
           homepage = "https://github.com/gruns/furl";
  
positive.code:         description = "URL manipulation made simple.";
        };
      };
      etesync = python37.pkgs.buildPythonPackage rec {
          pname = "etesync";
          version = "0.8.1";
  
negative.code:       python37Packages.six
        python37Packages.urllib3
        python37Packages.vobject
        radicale
        furl
        orderedmultidict
        pyscrypt
  