diff --git a/olah/proxy/tree.py b/olah/proxy/tree.py
index b0125a5..875930d 100644
--- a/olah/proxy/tree.py
+++ b/olah/proxy/tree.py
@@ -40,9 +40,7 @@ async def tree_proxy_cache(
 ):
     # save
     repos_path = app.app_settings.repos_path
-    save_dir = os.path.join(
-        repos_path, f"api/{repo_type}/{org}/{repo}/tree/{commit}"
-    )
+    save_dir = os.path.join(repos_path, f"api/{repo_type}/{org}/{repo}/tree/{commit}")
     save_path = os.path.join(save_dir, "tree.json")
     make_dirs(save_path)
 
@@ -116,9 +114,7 @@ async def tree_generator(
 
     # save
     repos_path = app.app_settings.repos_path
-    save_dir = os.path.join(
-        repos_path, f"api/{repo_type}/{org}/{repo}/tree/{commit}"
-    )
+    save_dir = os.path.join(repos_path, f"api/{repo_type}/{org}/{repo}/tree/{commit}")
     save_path = os.path.join(save_dir, "tree.json")
     make_dirs(save_path)
 
diff --git a/olah/server.py b/olah/server.py
index 9a127c6..20ba9f9 100644
--- a/olah/server.py
+++ b/olah/server.py
@@ -230,10 +230,10 @@ async def tree_proxy_common(repo_type: str, org: str, repo: str, commit: str, re
             git_path = os.path.join(mirror_path, repo_type, org, repo)
             if os.path.exists(git_path):
                 local_repo = LocalMirrorRepo(git_path, repo_type, org, repo)
-                meta_data = local_repo.get_tree(commit)
-                if meta_data is None:
+                tree_data = local_repo.get_tree(commit)
+                if tree_data is None:
                     continue
-                return JSONResponse(content=meta_data)
+                return JSONResponse(content=tree_data)
         except git.exc.InvalidGitRepositoryError:
             logger.warning(f"Local repository {git_path} is not a valid git reposity.")
             continue