anchor.diff: -{ lib, stdenv
  +{ lib
  +, stdenv
   , fetchFromGitHub
   , buildPythonPackage
  -, isPy27
  -, fetchpatch
  -# Mitmproxy requirements
  +, pythonOlder
  +  # Mitmproxy requirements
  +, asgiref
   , blinker
   , brotli
   , certifi
   , click
   , cryptography
   , flask
  +, h11
   , h2
   , hyperframe
   , kaitaistruct
   , ldap3
  +, msgpack
   , passlib
   , protobuf
  +, publicsuffix2
   , pyasn1
   , pyopenssl
   , pyparsing
  
positive.code:   disabled = pythonOlder "3.8";
  
    src = fetchFromGitHub {
      owner  = pname;
      repo   = pname;
      rev    = "v${version}";
      sha256 = "sha256-FyIZKFQtf6qvwo4+NzPa/KOmBCcdGJ3jCqxz26+S2e4=";
    };
  
    postPatch = ''
      # remove dependency constraints
      sed 's/>=\([0-9]\.\?\)\+\( \?, \?<\([0-9]\.\?\)\+\)\?\( \?, \?!=\([0-9]\.\?\)\+\)\?//' -i setup.py
    '';
  
    doCheck = (!stdenv.isDarwin);
  
    checkPhase = ''
      export HOME=$(mktemp -d)
      pytest -k 'not test_get_version' # expects a Git repository
    '';
  
    propagatedBuildInputs = [
      setuptools
  
negative.code: , tornado
  , urwid
  , wsproto
  , zstandard
    # Additional check requirements
  , beautifulsoup4
  , glibcLocales
  , hypothesis
  , parver
  , pytest-asyncio
  , pytest-timeout
  , pytest-xdist
  , pytestCheckHook
  , requests
  }:
  
  buildPythonPackage rec {
  