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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 _l2ycbcr(self, mode):
 """Convert from L to YCbCr. """

        self._check_modes(("L", "LA"))

        luma = self.channels[0]
        zeros = np.ma.zeros(luma.shape)
        zeros.mask = luma.mask

        self.channels = [luma, zeros, zeros] + self.channels[1:]

        if self.fill_value is not None:
            self.fill_value = [self.fill_value[0], 0, 0] + self.fill_value[1:]

        self.mode = mode