如何在PyQt5中访问qmenubar的qaction？

from PyQt5.QtWidgets import QApplication, QMainWindow, QAction, QMenuBar

class MyWindow(QMainWindow):
    def __init__(self):
        super().__init__()

        menubar = self.menuBar()
        file_menu = menubar.addMenu('File')

        action = QAction('Open', self)
        action.triggered.connect(self.open_file)
        file_menu.addAction(action)

    def open_file(self):
        # 处理打开文件的逻辑
        pass

if __name__ == '__main__':
    app = QApplication([])
    window = MyWindow()
    window.show()
    app.exec_()