|string> */ public function rules(): array { return [ 'submission_id' => 'nullable|exists:quiz_submissions,id', 'section_quiz_id' => 'required|exists:section_quizzes,id', 'user_id' => 'required|exists:users,id', 'answers' => 'required|array', 'answers.*' => 'required|array', 'answers.*.question_id' => 'required|exists:quiz_questions,id', 'answers.*.answer' => 'required|array', 'answers.*.answer.*' => 'required|string', ]; } }