creatinf a colormap using matplotlib OO

Hi list,

I tryied to find out how i display the colorbar like in the pocolor_demo for example but using matplotlib OO.

        self.fig = Figure(figsize=(self.hSize,self.vSize), dpi=self.res)
        X,Y = meshgrid(self.valueList, self.valueList2)
        self.a.pcolor(X, Y, self.valueList3, shading='flat')

self.fig.colorbar() requires a mappable argument. However i don't know with which element i must feed the colorbar method.
Has anyone succeed in display the colorbar with matplotlib OO?

Thanks a lot,
Philippe Collet