anchor.diff:        ln -s ${openaiMerges} openai-gpt-merges.txt )
     '';
   
  -  postPatch = ''
  -    echo 'import multiprocessing; multiprocessing.set_start_method("fork")' >> tests/__init__.py
  +  preCheck = ''
  +    export HOME=$(mktemp -d);
     '';
   
  -  preCheck = ''
  -    HOME=$TMPDIR
  -  '';
  +  pythonImportsCheck = [
  +    "tokenizers"
  +  ];
   
     disabledTests = [
  -    # Downloads data using the datasets module.
  +    # Downloads data using the datasets module
       "TestTrainFromIterators"
  +    # Those tests require more data
  +    "test_from_pretrained"
  +    "test_from_pretrained_revision"
  +    "test_continuing_prefix_trainer_mistmatch"
     ];
   
     meta = with lib; {
  +    description = "Fast State-of-the-Art Tokenizers optimized for Research and Production";
       homepage = "https://github.com/huggingface/tokenizers";
  -    description = "Fast State-of-the-Art Tokenizers optimized for Research and Production";
       license = licenses.asl20;
  +    maintainers = with maintainers; [ ];
       platforms = platforms.unix;
  -    maintainers = with maintainers; [ ];
     };
   }
  
positive.code:     url = "https://s3.amazonaws.com/models.huggingface.co/bert/openai-gpt-merges.txt";
      sha256 = "09a754pm4djjglv3x5pkgwd6f79i2rq8ydg0f7c3q1wmwqdbba8f";
    };
  in buildPythonPackage rec {
    pname = "tokenizers";
    version = "unstable-2021-08-13";
  
    src = fetchFromGitHub {
      owner = "huggingface";
      repo = pname;
      rev = "e7dd6436dd4a4ffd9e8a4f110ca68e6a38677cb6";
      sha256 = "1p7w9a43a9h6ys5nsa4g89l65dj11037p7a1lqkj4x1yc9kv2y1r";
    };
  
    cargoDeps = rustPlatform.fetchCargoTarball {
      inherit src sourceRoot;
      name = "${pname}-${version}";
      sha256 = "1yb4jsx6mp9jgd1g3mli6vr6mri2afnwqlmxq1rpvn34z6b3iw9q";
    };
  
    sourceRoot = "source/bindings/python";
  
    nativeBuildInputs = [ setuptools-rust ] ++ (with rustPlatform; [
      cargoSetupHook
      rust.cargo
      rust.rustc
    ]);
  
    buildInputs = lib.optionals stdenv.isDarwin [
      libiconv
    ];
  
  
negative.code: { lib
  , stdenv
  , buildPythonPackage
  , datasets
  , fetchFromGitHub
  , fetchurl
  , libiconv
  , numpy
  , openssl
  , pkg-config
  , pytestCheckHook
  , pythonOlder
  , requests
  , rustPlatform
  , setuptools-rust
  }:
  
  let
    # See https://github.com/huggingface/tokenizers/blob/main/bindings/python/tests/utils.py for details
    # about URLs and file names
    robertaVocab = fetchurl {
      url = "https://s3.amazonaws.com/models.huggingface.co/bert/roberta-base-vocab.json";
      sha256 = "0m86wpkfb2gdh9x9i9ng2fvwk1rva4p0s98xw996nrjxs7166zwy";
  