anchor.diff:  { lib
   , buildPythonPackage
   , fetchFromGitHub
  +, fetchpatch
   , pythonOlder
   , isPyPy
   , lazy-object-proxy
   , wrapt
  +, typing-extensions
   , typed-ast
   , pytestCheckHook
   , setuptools-scm
  
positive.code: 
    SETUPTOOLS_SCM_PRETEND_VERSION=version;
  
    nativeBuildInputs = [
      setuptools-scm
    ];
  
negative.code:   propagatedBuildInputs = [
      lazy-object-proxy
      wrapt
    ] ++ lib.optionals (pythonOlder "3.10") [
      typing-extensions
    ] ++ lib.optional (!isPyPy && pythonOlder "3.8") typed-ast;
  
    checkInputs = [
  