def close(self):
		'''关闭与数据库的连接'''
		if VERBOSE:
			print 'Database connection CLOSE.'
		self.conn.close()
def __init__(self, region, name, retention_in_days=7):
    super(LogGroup, self).__init__()
    self.region = region
    self.name = name
    self.retention_in_days = retention_in_days