From fe7f957ab2a42ae5669a0f66269c12acdbbd6b33 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Mon, 6 Jul 2020 09:31:10 +0530
Subject: [PATCH] ...

---
 src/calibre/srv/books.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/calibre/srv/books.py b/src/calibre/srv/books.py
index 06a9767854..a0e3a7b487 100644
--- a/src/calibre/srv/books.py
+++ b/src/calibre/srv/books.py
@@ -268,6 +268,7 @@ def update_annotations(ctx, rd, library_id, book_id, fmt):
         if val:
             alist.extend(val)
     db.merge_annotations_for_book(book_id, fmt, alist, user_type='web', user=user)
+    return b''
 
 
 mathjax_lock = Lock()