PyQt -如何将特定对话框与类链接

from PyQt5.QtWidgets import QApplication, QDialog, QPushButton
from PyQt5.QtCore import pyqtSignal, pyqtSlot

class MyDialog(QDialog):
    dialogClosed = pyqtSignal()  # 定义一个信号

    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        self.setWindowTitle('My Dialog')
        self.button = QPushButton('Close Dialog', self)
        self.button.clicked.connect(self.close)

    def closeEvent(self, event):
        self.dialogClosed.emit()  # 对话框关闭时发出信号

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        self.setWindowTitle('Main Window')
        self.button = QPushButton('Open Dialog', self)
        self.button.clicked.connect(self.openDialog)

    def openDialog(self):
        dialog = MyDialog()
        dialog.dialogClosed.connect(self.onDialogClosed)  # 将对话框的信号与槽函数链接
        dialog.exec_()

    @pyqtSlot()
    def onDialogClosed(self):
        print('Dialog closed')

if __name__ == '__main__':
    app = QApplication(sys.argv)
    mainWindow = MainWindow()
    mainWindow.show()
    sys.exit(app.exec_())