anchor.diff:  { lib
  +, attrs
   , buildPythonPackage
   , fetchPypi
  +, mock
   , pythonOlder
  +, repeated-test
  +, setuptools-scm
   , sphinx
  -, mock
  -, repeated-test
   , unittestCheckHook
  -, attrs
  -, setuptools-scm
   }:
   
   buildPythonPackage rec {
  
positive.code:     unittestCheckHook
    ];
  
    meta = with lib; {
      description = "Utilities for working with 3.3's inspect.Signature objects.";
      homepage = "https://pypi.python.org/pypi/sigtools";
      license = licenses.mit;
    };
  
  }
  
negative.code: 
    src = fetchPypi {
      inherit pname version;
      hash = "sha256-S44TWpzU0uoA2mcMCTNy105nK6OruH9MmNjnPepURFw=";
    };
  
    nativeBuildInputs = [
  