anchor.diff:  
     autopep8 = callPackage ../development/python-modules/autopep8 { };
   
  -  av = callPackage ../development/python-modules/av { };
  +  av = callPackage ../development/python-modules/av {
  +    inherit (pkgs) pkgconfig;
  +  };
   
     avro = callPackage ../development/python-modules/avro {};
   
  
positive.code:   pythonnet = callPackage ../development/python-modules/pythonnet {
      # `mono >= 4.6` required to prevent crashes encountered with earlier versions.
      mono = pkgs.mono4;
    };
  
    pytz = callPackage ../development/python-modules/pytz { };
  
negative.code: 
    pyshp = callPackage ../development/python-modules/pyshp { };
  
    pysmbc = callPackage ../development/python-modules/pysmbc {
      inherit (pkgs) pkgconfig;
    };
  
    pyspread = callPackage ../development/python-modules/pyspread { };
  
  