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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 md5(self):
 """Return md5 from meta, or compute it if absent."""

        md5 = self.meta.get("md5")
        if md5 is None:
            md5 = str(hashlib.md5(self.value).hexdigest())

        return md5