def _process_bKGD(self, data):
        try:
            if self.colormap:
                if not self.plte:
                    warnings.warn(
                      "PLTE chunk is required before bKGD chunk.")
                self.background = struct.unpack('B', data)
            else:
                self.background = struct.unpack("!%dH" % self.color_planes,
                  data)
        except struct.error:
            raise FormatError("bKGD chunk has incorrect length.")
dataset/ETHPy150Open jyapayne/Web2Executable/png.py/Reader._process_bKGD/original