public function examLearnerByCourse($courseid)
 {
     $exam = Exam::with('members')->whereHas('members', function ($member) {
         return $member->where('user_id', $this->user->id);
     })->where('course_id', $courseid)->get();
     return $exam;
 }
 public function checkExamTimeout(Exam $exam, $attempt = 1)
 {
     $member = $exam->members()->where('user_id', $this->user->id)->first();
     if ($member) {
         if ($member->finished_at->diffInSeconds(Carbon::now(), false) < 0) {
             return true;
         }
     }
     return false;
 }