Python pyside2 qtcharts在一个月后更新其自身

我正在尝试制作一张图表，如果本月结束，图表将在下个月更新，任何有想法或解决方案的人我都将非常感激

 def create_bar(self):
     # The QBarSet class represents a set of bars in the bar chart.
     # It groups several bars into a bar set

     set0 = QtCharts.QBarSet("markup")
     set1 = QtCharts.QBarSet("liabil")
     # set data
     # initial data = current sales and expenses
     if datetime.now().day == datetime.now().month:
          set0 << self.total_sales()
          set1 << self.total_expenses()
     

     # load data to chart
      series = QtCharts.QBarSeries()
        series.append(set0)
        series.append(set1)
        # initialize chart
        chart = QtCharts.QChart()
        chart.addSeries(series)
        chart.setAnimationOptions(QtCharts.QChart.SeriesAnimations)

        categories = datetime.now().strftime('%b')
        axis = QtCharts.QCategoryAxis()
        axisY = QtCharts.QValueAxis()
        axis.append(str(categories), 0)
        chart.addAxis(axisY, QtCore.Qt.AlignLeft)
        series.attachAxis(axisY)
        axisY.setRange(0, 10000)
        chart.setAxisX(axis, series)

        chart.legend().setVisible(True)
        chart.legend().setAlignment(Qt.AlignBottom)

        self.place = QtWidgets.QVBoxLayout(self)
        self.place = QtWidgets.QVBoxLayout(self.ui.widget_2)
        self.place.setContentsMargins(0, 0, 0, 0)
        self.chartview = QtCharts.QChartView(chart)
        self.chartview.setRenderHint(QPainter.Antialiasing)
        self.chartview.setContentsMargins(0, 0, 0, 0)
        self.place.addWidget(self.chartview)

def创建工具栏（自）：
#QBarSet类表示条形图中的一组条形图。
#它将多个条分组为一个条集
set0=QtCharts.QBarSet（“标记”）
set1=QtCharts.QBarSet（“liabil”）
#设置数据
#初始数据=当前销售额和费用
如果datetime.now（）.day==datetime.now（）.month：
set0请提供一个