如何在PyQt5 QtChart中刷新数据？

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow
from PyQt5.QtChart import QChart, QChartView, QLineSeries, QValueAxis, QLegend
from PyQt5.QtCore import Qt, QTimer

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

        # 创建QChart对象
        self.chart = QChart()

        # 创建QChartView对象，并设置QChart对象为其属性
        self.chart_view = QChartView(self.chart)
        self.setCentralWidget(self.chart_view)

        # 创建QLineSeries对象，并添加到QChart对象中
        self.series = QLineSeries()
        self.chart.addSeries(self.series)

        # 创建QValueAxis对象，并设置坐标轴的范围和标签
        self.axis_x = QValueAxis()
        self.axis_x.setRange(0, 10)
        self.axis_x.setLabelFormat("%.1f")
        self.axis_x.setTitleText("X")
        self.chart.addAxis(self.axis_x, Qt.AlignBottom)
        self.series.attachAxis(self.axis_x)

        self.axis_y = QValueAxis()
        self.axis_y.setRange(0, 100)
        self.axis_y.setLabelFormat("%d")
        self.axis_y.setTitleText("Y")
        self.chart.addAxis(self.axis_y, Qt.AlignLeft)
        self.series.attachAxis(self.axis_y)

        # 创建QLegend对象，并添加到QChart对象中
        self.legend = QLegend()
        self.chart.setLegend(self.legend)

        # 初始化数据
        self.data = [(i, i*i) for i in range(11)]
        self.index = 0

        # 创建定时器，每秒更新一次数据
        self.timer = QTimer()
        self.timer.timeout.connect(self.update_data)
        self.timer.start(1000)

    def update_data(self):
        # 更新数据系列对象的数据
        self.series.clear()
        self.series.append(self.data[self.index])
        self.index = (self.index + 1) % len(self.data)

        # 强制刷新图表显示
        self.chart.update()

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec_())