anchor.diff:  , libsodium
   , cffi
   , hypothesis
  -, stdenv
  -, six
   }:
   
   buildPythonPackage rec {
     pname = "pynacl";
     version = "1.5.0";
  +  format = "setuptools";
  +
     disabled = pythonOlder "3.6";
   
     src = fetchPypi {
  
positive.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;
    };
  }
  
negative.code: 
    propagatedBuildInputs = [
      cffi
    ];
  
    checkInputs = [
  