anchor.diff:    src = fetchPyPi {
       package = "pytest-benchmark";
       inherit version;
  -    type = ".zip";
  -    sha256 = "cec1d1d259b9869ac306f91936f9607508a119c34f21cca79d50521bc29bf980";
  +    sha256 = "185526b10b7cf1804cb0f32ac0653561ef2f233c6e50a9b3d8066a9757e36480";
     };
   
     nativeBuildInputs = [
  
positive.code:   ];
  
    propagatedBuildInputs = [
      pytest
      statistics
    ];
  
    doCheck = true;
  
    meta = with lib; {
      description = "py.test fixture for benchmarking code";
  
negative.code: { stdenv
  , buildPythonPackage
  , fetchPyPi
  , isPy2
  , lib
  , unzip
  
  , py-cpuinfo
  , pytest
  , statistics
  }:
  
  let
    inherit (lib) optionals;
  
    version = "3.1.1";
  in
  buildPythonPackage rec {
    name = "pytest-benchmark-${version}";
  