<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _WX28_clipped_agg_as_bitmap(agg, bbox):
 """ Convert the region of a the agg buffer bounded by bbox to a wx.Bitmap. Note: agg must be a backend_agg.RendererAgg instance. """

    l, b, width, height = bbox.bounds
    r = l + width
    t = b + height

    srcBmp = wx.BitmapFromBufferRGBA(int(agg.width), int(agg.height),
        agg.buffer_rgba())
    srcDC = wx.MemoryDC()
    srcDC.SelectObject(srcBmp)

    destBmp = wx.EmptyBitmap(int(width), int(height))
    destDC = wx.MemoryDC()
    destDC.SelectObject(destBmp)

    destDC.BeginDrawing()
    x = int(l)
    y = int(int(agg.height) - t)
    destDC.Blit(0, 0, int(width), int(height), srcDC, x, y)
    destDC.EndDrawing()

    srcDC.SelectObject(wx.NullBitmap)
    destDC.SelectObject(wx.NullBitmap)

    return destBmp