diff --git a/itchat/storage/messagequeue.py b/itchat/storage/messagequeue.py
index db814b90..3b595509 100644
--- a/itchat/storage/messagequeue.py
+++ b/itchat/storage/messagequeue.py
@@ -13,7 +13,7 @@ def put(self, message):
         queue.Queue.put(self, Message(message))
 
 class Message(AttributeDict):
-    def download(self, fileName):
+    def download(self, fileName=None):
         if hasattr(self.text, '__call__'):
             return self.text(fileName)
         else: