diff --git a/qa_prompt.py b/qa_prompt.py
index a24724f..60001d5 100644
--- a/qa_prompt.py
+++ b/qa_prompt.py
@@ -1,7 +1,9 @@
 from typing import List, Tuple, Dict, Optional
 
+from towhee.operator import PyOperator
 
-class QAPrompt:
+
+class QAPrompt(PyOperator):
     def __init__(self):
         super().__init__()
         self._template = """Use the following pieces of context to answer the question at the end.