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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 get_area_def(self, dsid):
 """Get area definition for message. If latlong grid then convert to valid eqc grid. """

        msg = self._get_message(self._msg_datasets[dsid])
        try:
            return self._area_def_from_msg(msg)
        except (RuntimeError, KeyError):
            raise RuntimeError("Unknown GRIB projection information")