anchor.diff:    checkInputs = [
       beautifulsoup4 flask pytest
       requests glibcLocales
  +    asynctest parver pytest-asyncio
     ];
   
     meta = with stdenv.lib; {
  
positive.code:   checkPhase = ''
      export HOME=$(mktemp -d)
      export LC_CTYPE=en_US.UTF-8
      # test_echo resolves hostnames
      pytest -k 'not test_echo and not test_find_unclaimed_URLs '
    '';
  
    propagatedBuildInputs = [
  
negative.code: { stdenv, fetchFromGitHub, python3Packages, glibcLocales, fetchpatch }:
  
  with python3Packages;
  
  buildPythonPackage rec {
    pname = "mitmproxy";
    version = "4.0.4";
  
    src = fetchFromGitHub {
      owner  = pname;
      repo   = pname;
      rev    = "v${version}";
      sha256 = "14i9dkafvyl15rq2qa8xldscn5lmkk2g52kbi2hl63nzx9yibx6r";
    };
  
    patches = [
      (fetchpatch {
        # Tests failed due to expired test certificates,
        # https://github.com/mitmproxy/mitmproxy/issues/3316
        # TODO: remove on next update
        name = "test-certificates.patch";
        url = "https://github.com/mitmproxy/mitmproxy/commit/1b6a8d6acd3d70f9b9627ad4ae9def08103f8250.patch";
        sha256 = "03y79c25yir7d8xj79czdc81y3irqq1i3ks9ca0mv1az8b7xsvfv";
      })
    ];
  
    postPatch = ''
      # remove dependency constraints
  