public static async Task <IEnumerable <Question> > FindQuestionsForQuiz(
     this QuizDbContext dbContext,
     int quizId,
     CancellationToken cancellationToken)
 =>
 await(from quiz in dbContext.Quizes
       from question in quiz.Questions
           where quiz.Id == quizId
       select question).Include(qu => qu.Choices).ToListAsync(cancellationToken);
 public static async Task <Domain.Entities.Quiz> FindQuizAsync(
     this QuizDbContext dbContext,
     int quizId,
     CancellationToken cancellationToken)
 =>
 await(from quiz in dbContext.Quizes
           where quiz.Id == quizId
       select quiz)
 .Include(q => q.Questions)
 .ThenInclude(qs => qs.Choices)
 .FirstOrDefaultAsync(cancellationToken);