From 58e506d0cd4c8fd6440929298a448f9163817a09 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Thu, 3 Nov 2022 11:07:19 +0530
Subject: [PATCH] EPUB Input: Fix empty adobe page number template file causing
 conversion to fail. Fixes #1995551 [[Bug] Convert EPUB Fail (TypeError:
 cannot convert 'NoneType' object to
 bytes)](https://bugs.launchpad.net/calibre/+bug/1995551)

---
 src/calibre/ebooks/oeb/base.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/calibre/ebooks/oeb/base.py b/src/calibre/ebooks/oeb/base.py
index 6c3bfd13ea..1761acefa5 100644
--- a/src/calibre/ebooks/oeb/base.py
+++ b/src/calibre/ebooks/oeb/base.py
@@ -432,7 +432,7 @@ def serialize(data, media_type, pretty_print=False):
         if isinstance(data, str):
             data = data.encode('utf-8')
         return data + b'\n'
-    return bytes(data)
+    return b'' if data is None else bytes(data)
 
 
 ASCII_CHARS   = frozenset(codepoint_to_chr(x) for x in range(128))