def close(self):
		'''关闭与数据库的连接'''
		if VERBOSE:
			print 'Database connection CLOSE.'
		self.conn.close()
def _option_suite(self, value):
        opt = Optional(value)
        self.assert_(isinstance(opt, Optional))
        self.assert_(isinstance(deoption(opt), type(value)))
        self.assertEqual(deoption(opt), value)