anchor.diff:      owner = "esc";
       repo = pname;
       rev = "v${version}";
  -    sha256 = "1h283gzs4nx8lrarmr454zza52cilmnbdrqn1n33v3cn1rayl3c9";
  +    sha256 = "0b0zdq7d7k7f6p3wwc799347fraphbr20rxd1ysnc4xi1cj4wpmi";
     };
   
     buildInputs = [ git graphviz ];
  
positive.code:     '';
  
    meta = {
      description = "Tool for visualization of Git repositories.";
      homepage = https://github.com/esc/git-big-picture;
      license = stdenv.lib.licenses.gpl3;
      platforms = stdenv.lib.platforms.linux;
  
negative.code: 
  python2Packages.buildPythonApplication rec {
    pname = "git-big-picture";
    version = "0.10.1";
  
    name = "${pname}-${version}";
  
  