python qt5 菜单栏一级菜单响应单击事件

self.statusbar.setObjectName("statusbar")   
MainWindow.setStatusBar(self.statusbar)
self.actional1 = QAction(MainWindow)   # 声明action
self.actional1.setText('员工注册')  # 设置action 名称

#self.menubar.addAction(self.menu.menuAction())
self.menubar.addAction(self.actional1)  #添加到menubar

self.actional1.triggered.connect(self.reg_ygwin)  #链接槽函数

def reg_ygwin(self):
    self.nwin = reg_yg.reg_yg()
    self.nwin.show()