anchor.diff:  
   buildPythonPackage rec {
     pname = "transformers";
  -  version = "3.4.0";
  +  version = "3.5.1";
   
     src = fetchFromGitHub {
       owner = "huggingface";
       repo = pname;
       rev = "v${version}";
  -    sha256 = "1v09gryxsg57d2cjwagna1535m8mbxlazdbhsww210lxa818m5qj";
  +    sha256 = "02z5zz0rq7mbgdmsm2ccfdbca57qy7iqp0vc7jspsmdfif4acwia";
     };
   
     propagatedBuildInputs = [
  
positive.code: 
    postPatch = ''
      substituteInPlace setup.py \
        --replace "tokenizers == 0.9.2" "tokenizers"
    '';
  
    preCheck = ''
  
negative.code:     "test_tokenizer_from_pretrained"
      "test_tokenizer_from_tokenizer_class"
      "test_tokenizer_identifier_with_correct_config"
      "test_tokenizer_identifier_non_existent"
    ];
  
    meta = with stdenv.lib; {
  