diff --git a/plugins/downloaderhelper/__init__.py b/plugins/downloaderhelper/__init__.py
index 43b07cd..aef83ce 100644
--- a/plugins/downloaderhelper/__init__.py
+++ b/plugins/downloaderhelper/__init__.py
@@ -797,7 +797,7 @@ class DownloaderHelper(_PluginBase):
         else:
             return None
 
-    def __match_multi_level_root_domain(self, domain: str) -> Tuple[str, int]:
+    def __match_multi_level_root_domain(self, domain: str) -> Tuple[Optional[str], int]:
         """
         匹配多级根域名
         :param domain: 被匹配的域名