Getting “The Declaration Isn't Referenced” error in Flutter even though it is referenced in main.dart

I am completing the Angela Yu Flutter course, am working on the “Quizzler” project, and continue to get an error stating that the declaration in a dart file isn’t referenced, however it appears (to me) to be. Both getQuestionText and getQuestionAnswer are resulting in the same error. I have made sure to import quiz_brain.dart into main.dart. Any help would be very much appreciated.

excerpt from quiz_brain.dart:

  void nextQuestion (){
    if (_questionNumber < _questionBank.length){_questionNumber++;
  }

  String get() {
    return _questionBank[_questionNumber].questionText;
  }

    String getQuestionText (){
      return _questionBank[_questionNumber].questionText;
  }
  bool getQuestionAnswer () {
    return _questionBank[_questionNumber].questionAnswer;
  }
}

excerpt from main.dart:

Expanded(
          flex: 5,
          child: Padding(
            padding: EdgeInsets.all(10.0),
            child: Center(
              child: Text(
                quizBrain.getQuestionText(),
                textAlign: TextAlign.center,
                style: TextStyle(
                  fontSize: 25.0,
                  color: Colors.white,
                ),
              ),
            ),
          ),
        ),