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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 _require_bucket(self, bucket_name):
 """ Also try to create the bucket. """

        if not self.exists(bucket_name) and not self.claim_bucket(bucket_name):
            raise OFSException("Invalid bucket: %s" % bucket_name)
        return self._get_bucket(bucket_name)