anchor.diff:      tzlocal
     ] ++ lib.optionals (pythonOlder "3.9") [
       backports-zoneinfo
  -  ] ++ lib.optionals (pythonOlder "3.7") [
  -    backports-datetime-fromisoformat
     ];
   
     checkInputs = [
  
positive.code: 
  buildPythonPackage rec {
    pname = "exchangelib";
    version = "4.6.2";
    format = "setuptools";
  
    disabled = pythonOlder "3.6";
  
    src = fetchFromGitHub {
      owner = "ecederstrand";
      repo = pname;
      rev = "v${version}";
      sha256 = "1vax4xqjav6nr3kfkz390ism3cs69dxnbx6sc0f9ci4mn3rxjwdy";
    };
  
    propagatedBuildInputs = [
  
negative.code: { lib
  , backports-zoneinfo
  , buildPythonPackage
  , cached-property
  