anchor.diff:      httpx
       httpx-socks
       markdown-it-py
  -  ];
  +  ] ++ httpx.optional-dependencies.http2
  +  ++ httpx-socks.optional-dependencies.asyncio;
   
     # tests try to connect to network
     doCheck = false;
  
positive.code:     jinja2
      langdetect
      lxml
      h2
      pygments
      pyyaml
      redis
  
negative.code: { lib
  , python3
  , fetchFromGitHub
  }:
  
  python3.pkgs.buildPythonApplication rec {
    pname = "searxng";
    version = "unstable-2022-07-15";
  
    src = fetchFromGitHub {
      owner = pname;
      repo = pname;
      rev = "7bf4e8d12d1d0ee53bf71f7c3a4010ef936f25d9";
      sha256 = "sha256-Fuv9AoV9WnI6qMgj4Ve016RF8gaLXYgw89jRROcm/A8=";
    };
  
    postPatch = ''
  