anchor.diff:    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;
  +  ] ++ lib.optional (pythonOlder "3.8") typed-ast
  +  ++ lib.optional (pythonOlder "3.10") typing-extensions;
   
     meta = with lib; {
       description = "The uncompromising Python code formatter";
  
positive.code: 
  buildPythonPackage rec {
    pname = "black";
    version = "21.12b0";
  
    disabled = pythonOlder "3.6";
  
    src = fetchPypi {
      inherit pname version;
      hash = "sha256-d7gPaTpWni5SeVhFljTxjfmwuiYluk4MLV2lvkLm8rM=";
    };
  
    nativeBuildInputs = [ setuptools-scm ];
  
negative.code: { stdenv
  , lib
  , buildPythonPackage
  , fetchPypi
  , pythonOlder
  , setuptools-scm
  , pytestCheckHook
  , aiohttp
  , aiohttp-cors
  , click
  , colorama
  , dataclasses
  