public function deleteClass($classId)
 {
     try {
         $tId = session('instId');
         $class = new \Home\Model\ClassModel();
         $class->startTrans();
         $result = $class->deleteClass($classId, $tId);
         $class->deleteClassDetails($classId, $tId);
         $class->deleteClassDetailAndStudentRelas($classId, $tId);
         $class->commit();
         $data = "true";
     } catch (Exception $e) {
         $class->rollback();
         $data = "false";
     }
     $this->ajaxReturn($data);
 }