diff --git a/milvus.py b/milvus.py
index 890e530..c464478 100644
--- a/milvus.py
+++ b/milvus.py
@@ -1,11 +1,12 @@
 import numpy as np
 from towhee import register
 from urllib.parse import urlsplit
+from towhee.operator import PyOperator
 from pymilvus import connections, Collection
 
 
 @register(output_schema=['mr'])
-class Milvus:
+class Milvus(PyOperator):
     """
     Milvus ANN index class.
     """