anchor.diff:  { lib
   , buildPythonPackage
  -, fetchPypi
  +, fetchFromGitHub
   , pythonOlder
   , mpmath
   , numpy
  
positive.code: , pytestCheckHook
  , matplotlib
  , dufte
  , isPy27
  }:
  
  buildPythonPackage rec {
    pname = "accupy";
    version = "0.3.6";
    disabled = isPy27;
  
    src = fetchPypi {
      inherit pname version;
      sha256 = "ad408f2937c22a0628fa8a73856e813c825064a14240cbfd64337d2a45a756c3";
    };
  
    nativeBuildInputs = [
  
negative.code:   ] ++ lib.optional (pythonOlder "3.8") importlib-metadata;
  
    checkInputs = [
      perfplot
      pytestCheckHook
      matplotlib
      dufte
  