raise NotOneValueFound('Expected one value, found 0') executing.executing.NotOneValueFound: Expected one value, found 0

[solemnrole]

from pymilvus import connections, Collection, FieldSchema, CollectionSchema, DataType,MilvusClient
client = MilvusClient(uri="http://localhost:19530")
我利用readme文件，链接client会出现以下错误:
raise NotOneValueFound('Expected one value, found 0') executing.executing.NotOneValueFound: Expected one value, found 0

[junjiejiangjjj]

hi @solemnrole , what versions of Pymilvus and milvus are you using?