anchor.diff:    };
   
     checkInputs = [
  -    pytest
       pyopenssl
       service-identity
  +    pytestCheckHook
     ];
   
     propagatedBuildInputs = [
  
positive.code:     futures
    ];
  
    checkPhase = ''
      pytest
    '';
  
    # Some of the tests use localhost networking.
    __darwinAllowLocalNetworking = true;
  
negative.code: { lib
  , stdenv
  , buildPythonPackage
  , fetchPypi
  , isPy3k
  , cryptography
  , futures ? null
  , pyopenssl
  , service-identity
  , pytestCheckHook
  , idna
  }:
  
  