PyQt中怎么绑定自定义函数到PushButton的clicked信号上

class MyDialog(Dialog):    def __init__(self):        Dialog.__init__(self)        #aa=self.pushButton.clicked()        self.pushButton.clicked.connect(self.show)        dd.        #self.trigger.connect(self.show)        #self.trigger.connect(self.showbox)            def showbox(self):        QtGui.QMessageBox.aboutQt(self,"AAA")        print("AAA")        pass