anchor.diff:  
   python3.pkgs.buildPythonApplication rec {
     pname = "tts";
  -  version = "0.4.2";
  +  version = "0.5.0";
  +  format = "setuptools";
   
     src = fetchFromGitHub {
       owner = "coqui-ai";
       repo = "TTS";
       rev = "v${version}";
  -    sha256 = "sha256-8a68iFbqqKwtZvufu1Vnv6hGHIQ3HU34wjuQsmr1NUA=";
  +    sha256 = "sha256-9fNYNhHS9wqrk2bZnrkkGU1OaDu/16RA8fz+Zj9xsyQ=";
     };
   
  -  postPatch = ''
  -    sed -i requirements.txt \
  -      -e 's!librosa==[^"]*!librosa!' \
  -      -e 's!gruut\[.*\]~=2.0.0!gruut!' \
  -      -e 's!mecab-python3==[^"]*!mecab-python3!' \
  -      -e 's!numba==[^"]*!numba!' \
  -      -e 's!numpy==[^"]*!numpy!' \
  -      -e 's!umap-learn==[^"]*!umap-learn!'
  +  postPatch = let
  +    relaxedConstraints = [
  +      "gruut"
  +      "librosa"
  +      "mecab-python3"
  +      "numba"
  +      "numpy"
  +      "umap-learn"
  +      "torch"
  +    ];
  +  in ''
  +    sed -r -i \
  +      ${lib.concatStringsSep "\n" (map (package:
  +        ''-e 's/${package}.*[<>=]+.*/${package}/g' \''
  +      ) relaxedConstraints)}
  +    requirements.txt
     '';
   
     nativeBuildInputs = with python3.pkgs; [
  
positive.code:     coqpit
      flask
      fsspec
      gruut
      gdown
      inflect
      jieba
      librosa
  
negative.code:     pandas
      pypinyin
      pysbd
      pytorch-bin
      pyworld
      scipy
      soundfile
      tensorboardx
      tensorflow
      torchaudio-bin
      tqdm
      umap-learn
      unidic-lite
      webrtcvad
    ];
  
    postInstall = ''
  