anchor.diff:  { lib
   , stdenv
  +, pythonOlder
   , brotli
   , brotlicffi
   , buildPythonPackage
  
positive.code:   pname = "requests";
    version = "2.27.1";
  
    src = fetchPypi {
      inherit pname version;
      hash = "sha256-aNfFb9WomZiHco7zBKbRLtx7508c+kdxT8i0FFJcmmE=";
  
negative.code:   ];
  
    propagatedBuildInputs = [
      brotlicffi
      certifi
      charset-normalizer
      idna
      urllib3
    ];
  
    passthru.optional-dependencies = {
      security = [];
      socks = [
        pysocks
      ];
      use_chardet_on_py3 = [
        chardet
      ];
    };
  
    checkInputs = [
      pytest-mock
      pytest-xdist
      pytestCheckHook
    ]
    ++ passthru.optional-dependencies.socks;
  
    # AttributeError: 'KeywordMapping' object has no attribute 'get'
    doCheck = !isPy27;
  