anchor.diff:  
       install -dm755 "$out/share/doc/nvpy/"
       install -m644 README.rst "$out/share/doc/nvpy/README"
  -
  -    wrapProgram $out/bin/nvpy --set TK_LIBRARY "${tk}/lib/${tk.libPrefix}"
     '';
   
     meta = with pkgs.lib; {
  
positive.code:     sha256 = "1rd3vlaqkg16iz6qcw6rkbq0jmyvc0843wa3brnvn1nz0kla243f";
    };
  
    buildInputs = [tk];
  
    propagatedBuildInputs = [
      pythonPackages.markdown
      pythonPackages.tkinter
      pythonPackages.docutils
    ];
  
    postInstall = ''
      install -dm755 "$out/share/licenses/nvpy/"
  
negative.code: { pkgs, fetchurl, tk, python2Packages }:
  
  let
    pythonPackages = python2Packages;
  in pythonPackages.buildPythonApplication rec {
    version = "0.9.7";
    name = "nvpy-${version}";
  
  