[PyQt] command require close window

[Krissstian]

Hi,
I have defined a command for a button wich terminates like this:

 # save map data to data object
                    data = io.BytesIO()
                    m.save(data, close_file=False)

                    webView = QWebEngineView()
                    webView.setHtml(data.getvalue().decode())
                    layout.addWidget(webView)

            if __name__ == '__main__':
                app = QApplication(sys.argv)
                app.setStyleSheet('''
                    QWidget {
                        font-size: 35px;
                    }
                ''')

                myApp = MyApp()
                myApp.show()


                try:
                    sys.exit(app.exec_())
                except SystemExit:
                    print('Closing Window...')

The problem is that when finnish to execute the command it also require to close the main window. where's the mistake, thanks.