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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 create(self, volume_id, backup_id=None, timestamp=None):
 """ create a backup of a volume """

        backup_id = backup_id or str(uuid.uuid4())
        timestamp = timestamp or int(time())
        return self.http_put('/volumes/%s/backups/%s' % (volume_id, backup_id),
                             params={'timestamp': timestamp})