pyqt4 close window by customed function

    def closeEvent(self, QCloseEvent):
        reply = QtGui.QMessageBox.question(self, 'Message',
                                           'Are you sure to quit?',
                                           QtGui.QMessageBox.Yes,
                                           QtGui.QMessageBox.No)
        if reply == QtGui.QMessageBox.Yes:
            QCloseEvent.accept()
        else:
            QCloseEvent.ignore()