用pyqt5关闭窗口时如何关闭串口

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow
from PyQt5.QtCore import QObject, QEvent, pyqtSignal, pyqtSlot

class MainWindow(QMainWindow):
    closeSerialPort = pyqtSignal()  # 定义关闭串口的信号

    def __init__(self):
        super(MainWindow, self).__init__()
        # 初始化其他窗口相关代码

    def closeEvent(self, event):
        self.closeSerialPort.emit()  # 发射关闭串口的信号
        event.accept()  # 接受关闭事件

class SerialPortManager(QObject):
    def __init__(self):
        super(SerialPortManager, self).__init__()
        # 初始化串口相关代码
        self.serialPort = None

    def openSerialPort(self):
        # 打开串口的逻辑代码

    def closeSerialPort(self):
        # 关闭串口的逻辑代码

if __name__ == '__main__':
    app = QApplication(sys.argv)
    mainWindow = MainWindow()
    serialPortManager = SerialPortManager()
    mainWindow.closeSerialPort.connect(serialPortManager.closeSerialPort)  # 将关闭串口的信号连接到关闭串口的槽函数
    mainWindow.show()
    sys.exit(app.exec_())