public static function listStudentFeesView($studentId)
 {
     $feeModel = new FeeModel();
     $studentModel = new StudentModel();
     $payedFees = $feeModel->getPaidFeesOfStudent($studentId);
     $unPayedFees = $feeModel->getUnPaidFeesOfStudent($studentId);
     $student = $studentModel->getStudent($studentId);
     $expiredFees = $feeModel->getExpiredFeesOfStudent($studentId);
     $view = new ListStudentFeesView();
     $view->show($payedFees, $unPayedFees, $expiredFees, $student);
 }
        if (isset($_POST['is-trainer']) && $_POST['is-trainer'] == 'true') {
            $trainer = TrainerModel::getTrainerFromDB($userID, $p_wd);
            if ($trainer != null) {
                session_start();
                $_SESSION['isTrainer'] = 'true';
                $_SESSION['trainer_id'] = $userID;
                // add user-id to session
                $_SESSION['name'] = $trainer['name'];
                // add name to session
                header("Location: home-trainer");
            } else {
                $error = "<div class='alert alert-danger'>Username or password was not entered correctly - please try again</div>";
                include_once "../index.php";
            }
        } else {
            $student = StudentModel::getStudent($userID, $p_wd);
            if ($student != null) {
                session_start();
                $_SESSION['isTrainer'] = 'false';
                $_SESSION['student_id'] = $userID;
                // add user-id to session
                $_SESSION['name'] = $student['name'];
                // add name to session
                header("Location: home-student");
            } else {
                $error = "<div class='alert alert-danger'>Username or password was not entered correctly - please try again</div>";
                include_once "../index.php";
            }
        }
    }
} else {