diff --git a/other/API_sign.md b/other/API_sign.md
index e4f71ab..e4f456c 100644
--- a/other/API_sign.md
+++ b/other/API_sign.md
@@ -36,7 +36,7 @@ def appsign(params, appkey, appsec):
     query = urllib.parse.urlencode(params) # 序列化参数
     sign = hashlib.md5((query+appsec).encode()).hexdigest() # 计算 api 签名
     params.update({'sign':sign})
-	return params
+    return params
 
 appkey = '1d8b6e7d45233436'
 appsec = '560c52ccd288fed045859ed18bffd973'