'get the axes bounding box in display space; *args* and
*kwargs* are empty'

def get_window_extent(self, *args, **kwargs):

    bbox = self.bbox
    x_pad = self.xaxis.get_tick_padding()
    y_pad = self.yaxis.get_tick_padding()
    return mtransforms.Bbox([[(bbox.x0 - x_pad), (bbox.y0 - y_pad)], [(bbox.x1 + x_pad), (bbox.y1 + y_pad)]])
