def METHOD_NAME(agg, bbox):
    """
    Convert the region of the agg buffer bounded by bbox to a wx.Image.  If
    bbox is None, the entire buffer is converted.
    Note: agg must be a backend_agg.RendererAgg instance.
    """
    if bbox is None:
        # agg => rgb -> image
        image = wxc.EmptyImage(int(agg.width), int(agg.height))
        image.SetData(agg.tostring_rgb())
        return image
    else:
        # agg => rgba buffer -> bitmap => clipped bitmap => image
        return wx.ImageFromBitmap(_WX28_clipped_agg_as_bitmap(agg, bbox))