def print_usage(self):
        print 'Total Usage: %f compute seconds' % self.box_usage
        cost = self.box_usage * 0.14
        print 'Approximate Cost: $%f' % cost
Print the BoxUsage and approximate costs of all requests made on
dataset/ETHPy150Open darcyliu/storyboard/boto/sdb/connection.py/SDBConnection.print_usage