anchor.diff:    src = fetchPyPi {
       package = "Jinja2";
       inherit version;
  -    sha256 = "aab8d8ca9f45624f1e77f2844bf3c144d180e97da8824c2a6d7552ad039b5442";
  +    sha256 = "702a24d992f856fa8d5a7a36db6128198d0c21e1da34448ca236c42e92384825";
     };
   
     propagatedBuildInputs = [
  
positive.code: { stdenv
  , buildPythonPackage
  , fetchPyPi
  
  , markupsafe
  }:
  
  let
    version = "2.9.4";
  in
  buildPythonPackage rec {
    name = "Jinja2-${version}";
  
negative.code: 
    doCheck = true;
  
    meta = with lib; {
      description = "Jinja2 is a template engine written in pure Python";
      homepage = http://jinja.pocoo.org/;
      license = licenses.bsd3;
  