diff --git a/docs/en/samples/pre_post_processing/python/langchain/agent.py b/docs/en/samples/pre_post_processing/python/langchain/agent.py
index 441b28690d..371efacadc 100644
--- a/docs/en/samples/pre_post_processing/python/langchain/agent.py
+++ b/docs/en/samples/pre_post_processing/python/langchain/agent.py
@@ -16,7 +16,7 @@ import asyncio
 
 from langchain.agents import create_agent
 from langchain.agents.middleware import wrap_tool_call
-from langchain_core.messages import ToolMessage, messages_to_dict
+from langchain_core.messages import ToolMessage
 from langchain_google_vertexai import ChatVertexAI
 from toolbox_langchain import ToolboxClient