There is an identifier that is needed to be passed for this to work but I am not sure what identifier has to be called. Can someone help?

I am needing to make it so when I press the button, it goes through all those working functions, and then takes the user to the next page page_ApiBox().

I am getting an "Expected Identifier, but got ," Error on the Navigator.of(context)... line. I see that an identifier needs to be called inside of page_ApiBox(apibox: ))); but I am not sure what identifier is supposed to be called. Null does not work.

floatingActionButton: FloatingActionButton(backgroundColor: Color(0xFF7E57C2),
            onPressed: () {
            final api_key_input = _apiKeyController.text;
            print('User API: $api_key_input');
            getApi();
              //var post = json.decode(response.body);                                      *UNCOMMENT LATER*
              // INSERT HERE: Store API Key Value in Encrypted Box.
              //   MOCK API RESPONSE-----------------                                       *DELETE LATER*
              print('Verification Successful');
              addApi(api_key_input);
              Navigator.of(context).push(MaterialPageRoute(builder: (context)=>page_ApiBox(apibox: ,)));

            label: Text('Verify'); floatingActionButtonLocation: FloatingActionButtonLocation.centerFloat;},


class page_ApiBox extends StatefulWidget {
    const page_ApiBox({Key? key, required this.apibox,}) : super(key: key);
    final apiBox apibox;

    @override
    State<page_ApiBox> createState() => _page_ApiBoxState();
  }



  class _page_ApiBoxState extends State<page_ApiBox> {
    @override
    Widget build(BuildContext context) {
      return Scaffold(
          body: buildApiBox(context, widget.apibox)
      );
    }
  }