anchor.diff:  
     inherit doCheck;
   
  +  preCheck = ''
  +    # Some tests depends on executables on PATH
  +    PATH="$out/bin:${gunicorn}/bin:$PATH"
  +  '';
  +
     disabledTests = [
       # Tests are flaky
       "test_keep_alive_client_timeout"
  
positive.code:     gunicorn
      pytest-asyncio
      pytest-benchmark
      pytest-sanic
      pytest-sugar
      pytestCheckHook
      sanic-testing
  
negative.code: 
  buildPythonPackage rec {
    pname = "sanic";
    version = "21.9.1";
  
    src = fetchFromGitHub {
      owner = "sanic-org";
      repo = pname;
      rev = "v${version}";
      sha256 = "sha256-TRrJr/L8AXLAARPjhBi2FxNh+jvxxdeMN24cT1njmqY=";
    };
  
    postPatch = ''
      # Loosen dependency requirements.
      substituteInPlace setup.py \
        --replace '"pytest==6.2.5"' '"pytest"' \
        --replace '"gunicorn==20.0.4"' '"gunicorn"' \
        --replace '"pytest-sanic",' "" \
      # Patch a request headers test to allow brotli encoding
  