congress.common.eventlet_server.Server not work with latest oslo_service

oslo.service >= 0.2.0 now check type:

2015-07-02 09:08:01.220 INFO congress.common.eventlet_server [-] Starting /usr/local/bin/congress-server on 0.0.0.0:1789
2015-07-02 09:08:01.220 CRITICAL congress [-] TypeError: Service <congress.common.eventlet_server.Server object at 0x7f3c92 193e10> must an instance of <class 'oslo_service.service.ServiceBase'>!

2015-07-02 09:08:01.220 TRACE congress Traceback (most recent call last):
2015-07-02 09:08:01.220 TRACE congress File "/usr/local/bin/congress-server", line 10, in <module>
2015-07-02 09:08:01.220 TRACE congress sys.exit(main())
2015-07-02 09:08:01.220 TRACE congress File "/opt/stack/congress/congress/server/congress_server.py", line 103, in main
2015-07-02 09:08:01.220 TRACE congress serve(*servers)
2015-07-02 09:08:01.220 TRACE congress File "/opt/stack/congress/congress/server/congress_server.py", line 72, in serve
2015-07-02 09:08:01.220 TRACE congress server.launch_with(launcher)
2015-07-02 09:08:01.220 TRACE congress File "/opt/stack/congress/congress/server/congress_server.py", line 50, in launch_with
2015-07-02 09:08:01.220 TRACE congress launcher.launch_service(self.server)
2015-07-02 09:08:01.220 TRACE congress File "/usr/local/lib/python2.7/dist-packages/oslo_service/service.py", line 164, in launch_service
2015-07-02 09:08:01.220 TRACE congress _check_service_base(service)
2015-07-02 09:08:01.220 TRACE congress File "/usr/local/lib/python2.7/dist-packages/oslo_service/service.py", line 114, in _check_service_base
2015-07-02 09:08:01.220 TRACE congress % {'service': service, 'base': ServiceBase})
2015-07-02 09:08:01.220 TRACE congress TypeError: Service <congress.common.eventlet_server.Server object at 0x7f3c92193e10> must an instance of <class 'oslo_service.service.ServiceBase'>!
2015-07-02 09:08:01.220 TRACE congress
congress failed to start