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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 imdecode(self, s):
 """Decodes a string or byte string to an NDArray. See mx.img.imdecode for more details."""

        def locate():
            """Locate the image file/index if decode fails."""
            if self.seq is not None:
                idx = self.seq[(self.cur % self.num_image) - 1]
            else:
                idx = (self.cur % self.num_image) - 1
            if self.imglist is not None:
                _, fname = self.imglist[idx]
                msg = "filename: {}".format(fname)
            else:
                msg = "index: {}".format(idx)
            return "Broken image " + msg
        try:
            img = imdecode(s)
        except Exception as e:
            raise RuntimeError("{}, {}".format(locate(), e))
        return img