python注册的服务，在nacos的服务列表里能看到，但是在java里获取不到实例

python的注册代码
SERVER_ADDRESSES = "127.0.0.1:8848"
NAMESPACE = "public"
def func():
# no auth mode
client = nacos.NacosClient(SERVER_ADDRESSES, namespace=NAMESPACE)
client.send_heartbeat("python", "127.0.0.1", "5000")
print('send heartbeat')

java的获取代码
@RestController
public class TestController {

@Autowired
DiscoveryClient discoveryClient;
@Autowired
RestTemplate restTemplate;


@GetMapping("/hello")
public String sayHello() throws NacosException {

    List<ServiceInstance> list = discoveryClient.getInstances("python");
    ServiceInstance instance = list.get(0);
}

}
直接就报空指针了
java.lang.NullPointerException: null
at java.util.HashMap.putMapEntries(HashMap.java:500) ~[na:1.8.0_111]
at java.util.HashMap.putAll(HashMap.java:784) ~[na:1.8.0_111]
at com.alibaba.cloud.nacos.discovery.NacosServiceDiscovery.hostToServiceInstance(NacosServiceDiscovery.java:95) ~[spring-cloud-alibaba-nacos-discovery-2.2.0.RELEASE.jar:2.2.0.RELEASE]
这是什么原因啊？

Start with the Python registration snippet and the Java DiscoveryClient.getInstances("python") call, then inspect NacosServiceDiscovery.java at line 95 and reproduce the reported null-pointer stack trace. Done means identifying why the registered service cannot be converted or returned to Java and documenting a compatible registration or discovery setup.