void onIframeLoaded(Event event) {
    print("LOADED: " + uuid);
    if (_iFrameElement.src != "https://manabie.teacherdashboard.cerebry.co/?is_integrated=true") {
      _iFrameElement.src = "https://manabie.teacherdashboard.cerebry.co/?is_integrated=true";
    }
    else {
      const jwt =
        "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJ1c2VyX2lkIjo4NzksInVzZXJuYW1lIjoibXVkaXRAY2VyZWJyeS5jbyIsImV4cCI6MTY5NTA0NjkyOSwiZW1haWwiOiJtdWRpdEBjZXJlYnJ5LmNvIiwib3JpZ19pYXQiOjE2OTUwMzI1MjksImF1ZCI6IlB5dGhvbkFwaSIsImlzcyI6IkNlcmVicnkifQ.dzPi3x_0XGutA4GZqVeU5o_GjH2HGusqFVyFSNKtYNo";
      const classCode = 'TESTING-BOARD';
      Map<String, dynamic> data = {
        'cerebry-jwt-token': jwt,
        'class-selected': classCode,
      };
      _iFrameElement.contentWindow?.postMessage(
        jsonEncode(data),
        '*',
      );
    }
  }