code: def _convert_agg_to_wx_bitmap(agg, bbox):
      
      if bbox is None:
          # agg => rgba buffer -> bitmap
          return wx.BitmapFromBufferRGBA(int(agg.width), int(agg.height),
              agg.buffer_rgba())
      else:
          # agg => rgba buffer -> bitmap => clipped bitmap
          return _WX28_clipped_agg_as_bitmap(agg, bbox)
docs: Convert the region of the agg buffer bounded by bbox to a wx.Bitmap.  If
      bbox is None, the entire buffer is converted.
  
      Note: agg must be a backend_agg.RendererAgg instance.