anchor.diff:  
     src = fetchPypi {
       inherit pname version;
  -    sha256 = "d0da4c3d872a7d5796ac85016caa1da38ae902bebdc759e1b6c0f6f8b5802741";
  +    hash = "sha256-0NpMPYcqfVeWrIUBbKodo4rpAr69x1nhtsD2+LWAJ0E=";
     };
   
     buildInputs = [
  
positive.code: { stdenv
  , lib
  , buildPythonPackage
  , fetchPypi
  , pyannotate
  
negative.code:   propagatedBuildInputs = [
      pyannotate
    ];
  
    postPatch = ''
      substituteInPlace setup.py \
        --replace "pytest>=3.2.0,<7.0.0" "pytest>=3.2.0"
    '';
  
    # Module has no tests
    doCheck = false;
  