anchor.diff:    toolz = buildPythonPackage rec{
       name = "toolz-${version}";
       version = "0.7.2";
  -    
  +
       src = pkgs.fetchurl{
         url = "https://pypi.python.org/packages/source/t/toolz/toolz-${version}.tar.gz";
         md5 = "6f045541a9e7ee755b7b00fced4a7fde";
       };
  -    
  +
       meta = {
         homepage = "http://github.com/pytoolz/toolz/";
         description = "List processing tools and functional utilities";
  -      license = "licenses.bsd3";   
  -    };
  -  };
  -  
  +      license = "licenses.bsd3";
  +    };
  +  };
  +
     tox = buildPythonPackage rec {
       name = "tox-1.8.1";
   
  
positive.code:   multipledispatch = buildPythonPackage rec {
      name = "multipledispatch-${version}";
      version = "0.4.8";
     
      src = pkgs.fetchurl {
        url = "https://pypi.python.org/packages/source/m/multipledispatch/${name}.tar.gz";
        sha256 = "07d41fb3ed25e8424536e48a8566f88a0f9926ca4b6174bff6aa16c98251b92e";
      };
      
      meta = {
        homepage = http://github.com/mrocklin/multipledispatch/;
        description = "A relatively sane approach to multiple dispatch in Python";
  
negative.code:   odo = buildPythonPackage rec {
      name = "odo-${version}";
      version= "0.3.3";
  
      src = pkgs.fetchurl {
        url = "https://pypi.python.org/packages/source/o/odo/${name}.tar.gz";
        sha256 = "2499ee86c26c74daa28f21ed235ca331911065950deea5169ebdb7d5dae6ebef";
      };
  
      propagatedBuildInputs = with self; [ datashape numpy pandas toolz multipledispatch networkx ];
  
      meta = {
        homepage = https://github.com/ContinuumIO/odo;
        description = "Data migration utilities";
        license = licenses.bsdOriginal;
      };
    };
  
    offtrac = buildPythonPackage rec {
      name = "offtrac-0.1.0";
      meta.maintainers = with maintainers; [ mornfall ];
  