pyqt5 pygraph ‘MouseClickEvent‘ object is not subscriptable

两种绑定信号的方法获取的返回值不一样，第一种方法返回的event没有下标，event[0]会报错

self.scatter.scene().sigMouseClicked.connect(self.mouse_clicked)
print(event.pos().x())

self.proxy_clicked = pg.SignalProxy(self.scatter.scene().sigMouseClicked, rateLimit=60, slot=self.mouse_clicked)
print(event[0].pos().x())