diff --git a/lightrag/storage/nano_vector_db.py b/lightrag/storage/nano_vector_db.py
index 1499076c..f2372799 100644
--- a/lightrag/storage/nano_vector_db.py
+++ b/lightrag/storage/nano_vector_db.py
@@ -47,14 +47,10 @@ Usage:
     from lightrag.storage.networkx_storage import NetworkXStorage
 
 """
-
-
 import asyncio
-import html
 import os
 from tqdm.asyncio import tqdm as tqdm_async
 from dataclasses import dataclass
-from typing import Any, Union, cast, Dict
 import numpy as np
 import pipmaster as pm
 
@@ -66,18 +62,11 @@ import time
 
 from lightrag.utils import (
     logger,
-    load_json,
-    write_json,
     compute_mdhash_id,
 )
 
 from lightrag.base import (
-    BaseGraphStorage,
-    BaseKVStorage,
     BaseVectorStorage,
-    DocStatus,
-    DocProcessingStatus,
-    DocStatusStorage,
 )