diff --git a/youtube_dl/extractor/bilibili.py b/youtube_dl/extractor/bilibili.py
index 2cd26bd70..f91d7fb56 100644
--- a/youtube_dl/extractor/bilibili.py
+++ b/youtube_dl/extractor/bilibili.py
@@ -113,7 +113,7 @@ class BiliBiliIE(InfoExtractor):
             else:
                 return 0
 
-    def _calculate_size(self, durl: list) -> int:
+    def _calculate_size(self, durl):
         "Calculate total file size."
         s = 0
         for i in durl: