anchor.diff:    terminado = buildPythonPackage rec {
       name = "terminado-${version}";
       version = "0.5";
  -    
  +
       src = pkgs.fetchurl {
         url = "https://pypi.python.org/packages/source/t/terminado/${name}.tar.gz";
         sha256 = "63e893eff1ba84f1ee7c4bfcca7676ba1de6394538bb9aa80cbbc8866cb875b6";
       };
  -    
  +
       propagatedBuildInputs = with self; [ ptyprocess tornado ];
  -    
  +
       meta = {
         description = "Terminals served to term.js using Tornado websockets";
         homepage = https://github.com/takluyver/terminado;
         licenses = licenses.bsd2;
       };
     };
  -  
  +
     testscenarios = buildPythonPackage rec {
       name = "testscenarios-${version}";
       version = "0.4";
  
positive.code:   datashape = buildPythonPackage rec {
      name = "datashape-${version}";
      version = "0.4.6";
      
      src = pkgs.fetchurl {
        url = "https://pypi.python.org/packages/source/D/DataShape/${name}.tar.gz";
        sha256 = "0caa86a4347f1b0c45f3890d78d0b89662189c7dd6df3a8e5ff3532ae8bc434f";    
      };
      
      propagatedBuildInputs = with self; [ numpy multipledispatch dateutil ];
      
      meta = {
        homepage = https://github.com/ContinuumIO/datashape;
        description = "A data description language";
  
negative.code:       license = licenses.asl20;
      };
    };
  
    cytoolz = buildPythonPackage rec {
      name = "cytoolz-${version}";
      version = "0.7.3";
  
      src = pkgs.fetchurl{
        url = "https://pypi.python.org/packages/source/c/cytoolz/cytoolz-${version}.tar.gz";
        md5 = "e9f0441d9f340a23c60357f68f25d163";
      };
  
      meta = {
        homepage = "http://github.com/pytoolz/cytoolz/";
        description = "Cython implementation of Toolz: High performance functional utilities";
        license = "licenses.bsd3";
      };
    };
  
  