From 46782ad79b3c43fe76527a9ff9795515392e81d9 Mon Sep 17 00:00:00 2001
From: Shu <ngo38114@gmail.com>
Date: Mon, 19 Jun 2023 07:39:19 +0700
Subject: [PATCH] Fixed an unhandled error that was raised when DynamoDB did
 not have any chat history. (#6141)

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The current version of chat history with DynamoDB doesn't handle the
case correctly when a table has no chat history. This change solves this
error handling.

<!-- Remove if not applicable -->

Fixes https://github.com/hwchase17/langchain/issues/6088

#### Who can review?

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@hwchase17

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---
 langchain/memory/chat_message_histories/dynamodb.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/langchain/memory/chat_message_histories/dynamodb.py b/langchain/memory/chat_message_histories/dynamodb.py
index dfde1457..ef969922 100644
--- a/langchain/memory/chat_message_histories/dynamodb.py
+++ b/langchain/memory/chat_message_histories/dynamodb.py
@@ -44,6 +44,7 @@ class DynamoDBChatMessageHistory(BaseChatMessageHistory):
         """Retrieve the messages from DynamoDB"""
         from botocore.exceptions import ClientError
 
+        response = None
         try:
             response = self.table.get_item(Key={"SessionId": self.session_id})
         except ClientError as error: