code: def GetSubBitmap(self, x: int, y: int, width: int, height: int) -> 'Bitmap':
          
          colors = self.GetPixelColorsOfRect(x, y, width, height)
          bitmap = Bitmap(width, height)
          bitmap.SetPixelColorsOfRect(0, 0, width, height, colors)
          return bitmap
docs: x: int.
          y: int.
          width: int.
          height: int.
          Return `Bitmap`, a sub bitmap of the input rect.