anchor.diff:  { lib
   , buildPythonPackage
   , fetchFromGitHub
  -, fetchpatch
   , pytestCheckHook
   , pythonOlder
   , attrs
  
positive.code: 
  buildPythonPackage rec {
    pname = "markdown-it-py";
    version = "1.0.0";
    format = "pyproject";
  
    disabled = pythonOlder "3.6";
  
negative.code:     owner = "executablebooks";
      repo = pname;
      rev = "v${version}";
      sha256 = "0h7rn3rcqfwmnqs97qczwkw9w5g4df8bgn6sw7k149svfqgrkf56";
    };
  
    propagatedBuildInputs = [ attrs linkify-it-py ]
      ++ lib.optional (pythonOlder "3.8") typing-extensions;
  