def close(self):
		'''关闭与数据库的连接'''
		if VERBOSE:
			print 'Database connection CLOSE.'
		self.conn.close()
def _load_data(self, directory):
        try:
            with open(directory, 'r') as f:
                data = f.read()
                return literal_eval(data)
        except OSError as e:
            raise