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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 _update_meta(self):
 """ internal function to define the metadata regarding filename, location, and prefix. """

        for v in ["filename", "location", "prefix"]:
            if "meta" not in self:
                self["meta"] = {}
            self["meta"][v] = self[v]
            del self[v]