method for embedding a plot in wx

Hi,

I didn't get the way to embed a plot where I wish it to be, for example
inside a panel or a sizer?

I did the following :
I create a panel panel_4 which is where I'd like to get the plot, I create a
sizer sizer_8 in it and try to load the plot but the plot does not show. I
don't know how to solve this ?

In the __init__ of the frame I put this :

class MyFrame(wx.Frame):
    def __init__(self, *args, **kwds):
        ...
        self.panel_4 = wx.Panel(self.panel_1, -1)
        #matplotlib part initialisation
        self.fig = Figure((6,6), 75)
        self.canvas = FigureCanvasWx(self.panel_4, -1, self.fig)
        self.toolbar = NavigationToolbar2Wx(self.canvas)
        self.toolbar.Realize()
        # Create a figure manager to manage things
        self.figmgr = FigureManager(self.canvas, 1, self)
        #...

        sizer_8 = wx.BoxSizer(wx.VERTICAL)
        #...

        sizer_4.Add(sizer_5, 1, wx.EXPAND, 0)
        self.panel_4.SetAutoLayout (True)
        self.panel_4.SetSizer(sizer_8)
        sizer_8.Fit(self.panel_4)
        sizer_8.SetSizeHints(self.panel_4)
        sizer_8.Add(self.canvas, 1, wxLEFT|wxTOP|wxGROW)
        sizer_8.Add(self.toolbar , 0, wxGROW)