Jihoon Kang

``` E/flutter (19034): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: FormatException: Invalid date format E/flutter (19034): 0 E/flutter (19034): #0 DateTime.parse (dart:core/date_time.dart:347) E/flutter (19034): #1 NaverAccessToken.isValid (package:flutter_naver_login/flutter_naver_login.dart:109) E/flutter (19034): #2 FlutterNaverLogin.isLoggedIn (package:flutter_naver_login/flutter_naver_login.dart:32) E/flutter (19034):...

``` bool isValid() { if (expiresAt.isEmpty || expiresAt == 'no token') return false; bool timeValid = Clock.now().isBefore(DateTime.parse(expiresAt)); bool tokenExist = accessToken.isNotEmpty && accessToken != 'no token'; return timeValid && tokenExist;...