[wxPython] Problème avec wx.Grid

class SquareFrame(wx.Frame):
    
    def __init__(self, parent, title):
        wx.Frame.__init__(self, parent, wx.ID_ANY, title, size=(500, 300))
        self.parent = parent
        self.initialize()
        
    def initialize(self):
        main_sizer = wx.BoxSizer(wx.VERTICAL)
        self.SetSizer(main_sizer)
        
        main_sizer.Add(wx.StaticText(self, label='Bâtiments'))
        self.grid = wx.grid.Grid(self)
        
        self.grid.CreateGrid(4,3)
        
        hunterhutimg = wx.Bitmap('images/buildings/HunterHut.png')
        farmimgimg = wx.Bitmap('images/buildings/Farm.png')
        
        hunterhutimgagerenderer = MyImageRenderer(hunterhutimg)
        self.grid.SetCellRenderer(0, 0, hunterhutimgagerenderer)
        self.grid.SetColSize(0, hunterhutimg.GetWidth() + 2)
        self.grid.SetRowSize(0, hunterhutimg.GetHeight() + 2)
        
        farmimgimgagerenderer = MyImageRenderer(farmimgimg)
        self.grid.SetCellRenderer(1, 0, farmimgimgagerenderer)
        self.grid.SetColSize(0, farmimgimg.GetWidth() + 2)
        self.grid.SetRowSize(0, farmimgimg.GetHeight() + 2)
        
        main_sizer.Add(self.grid)
        
        self.Show(True)