anchor.diff:  
     doCheck = (!stdenv.isDarwin);
   
  -  # examples.complex.xss_scanner doesn't import correctly with pytest5
     checkPhase = ''
       export HOME=$(mktemp -d)
  -    export LC_CTYPE=en_US.UTF-8
  -    pytest --ignore test/examples \
  -      -k 'not test_find_unclaimed_URLs and not test_tcp'
  +    pytest -k 'not test_get_version' # expects a Git repository
     '';
   
     propagatedBuildInputs = [
  
positive.code: 
  buildPythonPackage rec {
    pname = "mitmproxy";
    version = "5.1.1";
    disabled = isPy27;
  
    src = fetchFromGitHub {
      owner  = pname;
      repo   = pname;
      rev    = "v${version}";
      sha256 = "1lirlckpvd3c6s6q3p32w4k4yfna5mlgr1x9g39lhzzq0sdiz3lk";
    };
  
    postPatch = ''
      # remove dependency constraints
  
negative.code: , fetchFromGitHub
  , buildPythonPackage
  , isPy27
  , fetchpatch
  # Mitmproxy requirements
  , blinker
  , brotli
  