why 'ServiceURL' object has no attribute 'interface', please help

[lichenjie]

File "C:\Users\Administrator.virtualenvs\athena-web-6sHZPCaj\lib\site-packages\dubbo_client\rpclib.py", line 34, in init self.registry.subscribe(interface) File "C:\Users\Administrator.virtualenvs\athena-web-6sHZPCaj\lib\site-packages\dubbo_client\registry.py", line 205, in subscribe self._compare_swap_nodes(interface, self.__unquote(children)) File "C:\Users\Administrator.virtualenvs\athena-web-6sHZPCaj\lib\site-packages\dubbo_client\registry.py", line 129, in _compare_swap_nodes self._add_node(interface, service_url) File "C:\Users\Administrator.virtualenvs\athena-web-6sHZPCaj\lib\site-packages\dubbo_client\registry.py", line 89, in _add_node key = self._to_key(service_url.interface, service_url.version, service_url.group) AttributeError: 'ServiceURL' object has no attribute 'interface'