anchor.diff:  { lib
  +, stdenv
   , buildPythonPackage
   , fetchPypi
   , pytestCheckHook
  
positive.code: 
    propagatedBuildInputs = [
      cffi
      six
    ];
  
    checkInputs = [
  
negative.code: 
    SODIUM_INSTALL = "system";
  
    pythonImportsCheck = [
      "nacl"
    ];
  
    meta = with lib; {
      description = "Python binding to the Networking and Cryptography (NaCl) library";
      homepage = "https://github.com/pyca/pynacl/";
      license = licenses.asl20;
      maintainers = with maintainers; [ ];
    };
  }
  