public function updateUser($userName, $userSurname, $userEmail, $userPassword, $userSchool, $userGrade, $userIdNumber, $userContact){
        $sql = "UPDATE edge_tuition.users SET userName = ?, userSurname = ?, userEmail = ?, userPassword = ?, "
            . "userSchool = ?, userGrade = ?, userIdNumber = ?, userContact = ? WHERE ";
        $stmt->this->dbConnection->prepare($sql);
        $stmt->execute();
        $stmt->storeResult();
        return $stmt;
    }