namespace "public" is "" in program,add_naming_instance and send_heartbeat cluster_name is different when this parameter is not entered

[HWTsang]

why is the "public" namespace be "" client.add_naming_instance("", "1.0.0.7", 8080)

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client.add_naming_instance("test.service1", "1.0.0.7", 8080) the cluster name will be None

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client.send_heartbeat("test.service1", "1.0.0.7", 8080) the cluster name will be DEFAULT

[Orangeices]

namespace参数写上public后，会出现两个集群，过一段时间集群名为None的会消失 ，剩下DEFAULT。