diff --git a/app/tool/search/__init__.py b/app/tool/search/__init__.py
index 70ea3d7..fe127ae 100644
--- a/app/tool/search/__init__.py
+++ b/app/tool/search/__init__.py
@@ -4,6 +4,7 @@ from app.tool.search.bing_search import BingSearchEngine
 from app.tool.search.duckduckgo_search import DuckDuckGoSearchEngine
 from app.tool.search.google_search import GoogleSearchEngine
 
+
 __all__ = [
     "WebSearchEngine",
     "BaiduSearchEngine",
diff --git a/app/tool/search/bing_search.py b/app/tool/search/bing_search.py
index 701841b..46955b5 100644
--- a/app/tool/search/bing_search.py
+++ b/app/tool/search/bing_search.py
@@ -6,6 +6,7 @@ from bs4 import BeautifulSoup
 from app.logger import logger
 from app.tool.search.base import WebSearchEngine
 
+
 ABSTRACT_MAX_LENGTH = 300
 
 USER_AGENTS = [
diff --git a/app/tool/web_search.py b/app/tool/web_search.py
index 8b80e46..cb13934 100644
--- a/app/tool/web_search.py
+++ b/app/tool/web_search.py
@@ -10,7 +10,7 @@ from app.tool.search import (
     BingSearchEngine,
     DuckDuckGoSearchEngine,
     GoogleSearchEngine,
-    WebSearchEngine
+    WebSearchEngine,
 )