anchor.diff:  
     src = fetchPypi {
       inherit pname version;
  -    sha256 = "sha256-S44TWpzU0uoA2mcMCTNy105nK6OruH9MmNjnPepURFw=";
  +    hash = "sha256-S44TWpzU0uoA2mcMCTNy105nK6OruH9MmNjnPepURFw=";
     };
   
     nativeBuildInputs = [
  
positive.code: { lib
  , buildPythonPackage
  , fetchPypi
  , pythonOlder
  , sphinx
  , mock
  , repeated-test
  , unittestCheckHook
  , attrs
  , setuptools-scm
  }:
  
  buildPythonPackage rec {
  
negative.code:     unittestCheckHook
    ];
  
    pythonImportsCheck = [
      "sigtools"
    ];
  
    meta = with lib; {
      description = "Utilities for working with inspect.Signature objects";
      homepage = "https://sigtools.readthedocs.io/";
      license = licenses.mit;
      maintainers = with maintainers; [ ];
    };
  }
  