diff --git a/app/account_service.py b/app/account_service.py
index 09439d5..02394e7 100644
--- a/app/account_service.py
+++ b/app/account_service.py
@@ -1,4 +1,6 @@
 from flask import *
+from markupsafe import escape
+
 from Login import check_username_availability, verify_user, add_user, get_expiry_date, change_password, WarningMessage
 
 
@@ -20,12 +22,12 @@ def signup():
         # POST方法需判断是否注册成功，再根据结果返回不同的内容
         username = escape(request.form['username'])
         password = escape(request.form['password'])
-        
+
         #! 添加如下代码为了过滤注册时的非法字符
         warn = WarningMessage(username)
         if str(warn) != 'OK':
             return str(warn)
-        
+
         available = check_username_availability(username)
         if not available: # 用户名不可用
             flash('用户名 %s 已经被注册。' % (username))
diff --git a/app/user_service.py b/app/user_service.py
index 79c7888..fbda760 100644
--- a/app/user_service.py
+++ b/app/user_service.py
@@ -1,6 +1,7 @@
 from datetime import datetime
 
 from flask import *
+from markupsafe import escape
 
 # from app import Yaml
 # from app.Article import get_today_article, load_freq_history