Matplotlib 我能'；t显示值引用到网格的图形

我正在创建一个有两个面板的GUI。一种是让用户输入日期和价格的网格。另一个是用于显示总费用的图表

我想从panel1中网格中的单元格中获取值。但是，我在panel2中看不到任何图表

请修复此代码，以便能够在网格中获取值，并在panel2中生成线性图

代码如下：

import wx
import wx.grid
import matplotlib
from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg
app = wx.App()

class MainFrame(wx.Frame): 
   def __init__(self, parent, title): 
      super().__init__(parent, title = title, size = (600,600))  
      self.InNotebook() 
         
   def InNotebook(self):    
      nb = wx.Notebook(self) 
      nb.AddPage(Panel1(nb),"Input Values")
      nb.AddPage(Panel2(nb),"Total Expense")
      self.Centre() 
      self.Show(True)

class Panel1(wx.Panel):
    def __init__(self, parent): 
      super(Panel1, self).__init__(parent)
      grid = wx.grid.Grid(self)
      grid.CreateGrid(5, 2)
      
      grid.SetColLabelValue(0, "dates")
      grid.SetColLabelValue(1, "Prices")

      grid.SetCellValue(0, 0, "20,21,23")
      grid.SetCellValue(0, 1, "453,363,567" ) 

      
      grid.AutoSize()

class Panel2(wx.Panel):
    
    def __init__(self, parent): 
      super(Panel2, self).__init__(parent)

    def GetValue(self):
      value_dates = self.grid.GetCellValue(self, 0, 0)
      value_prices = self.grid.GetCellValue(self, 0, 1)
    
    def Graph(self):
        value_dates = self.grid.GetCellValue(self, 0, 0)
        value_prices = self.grid.GetCellValue(self, 0, 1)
        figure = matplotlib.figure.Figure(self)
        self.canvas = FigureCanvasWxAgg(self, wx.ID_ANY, figure)
        self.plot1 = figure.add_subplot(211, xlabel='dates', ylabel='expense')
        self.plot1.plot(value_dates, value_prices, '-', color=clr[num%len(clr)], label='[$]')
        self.plot1.legend(loc='upper right')
        self.canvas.draw()

MainFrame(None, "Total Expense")
app.MainLoop()