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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def rgb(self):
 # type: () -> bytes """ Compute RGB values from the BGRA raw pixels. :return bytes: RGB pixels. """


        if not self.__rgb:
            rgb = bytearray(self.height * self.width * 3)
            raw = self.raw
            rgb[0::3] = raw[2::4]
            rgb[1::3] = raw[1::4]
            rgb[2::3] = raw[0::4]
            self.__rgb = bytes(rgb)

        return self.__rgb