anchor.diff: -{ stdenv, lib
  -, buildPythonPackage, fetchPypi, pythonOlder, setuptools-scm, pytestCheckHook
  +{ stdenv
  +, lib
  +, buildPythonPackage
  +, fetchPypi
  +, pythonOlder
  +, setuptools-scm
  +, pytestCheckHook
   , aiohttp
   , aiohttp-cors
  -, attrs
   , click
   , colorama
   , dataclasses
  
positive.code:   propagatedBuildInputs = [
      aiohttp
      aiohttp-cors
      attrs
      click
      colorama
      mypy-extensions
      pathspec
      platformdirs
      tomli
      typed-ast # required for tests and python2 extra
      uvloop
    ] ++ lib.optional (pythonOlder "3.7") dataclasses
      ++ lib.optional (pythonOlder "3.8") typing-extensions;
  
    meta = with lib; {
      description = "The uncompromising Python code formatter";
  
negative.code: 
  buildPythonPackage rec {
    pname = "black";
    version = "22.1.0";
  
    disabled = pythonOlder "3.6";
  
    src = fetchPypi {
      inherit pname version;
      hash = "sha256-p8AZLTVjX2/BF0vldct5FekuXdYp7nn9rw3PpBqAr7U=";
    };
  
    nativeBuildInputs = [ setuptools-scm ];
  