Here's the error I got running strip spans + smarten puncuation. If you need them run separately I can do that.
Code:
Modifying: C:\Users\[user]\AppData\Local\Temp\calibre_n7_o6tj0\k9ixvfiz_modify_epub\5036.epub
Parsing xml file: content.opf
Parsing xml file: toc.ncx
Applying smarten punctuation
No Cats Allowed - ERROR: Traceback (most recent call last):
File "calibre_plugins.modify_epub.modify", line 78, in process_book
File "calibre_plugins.modify_epub.modify", line 180, in _process_book
File "calibre_plugins.modify_epub.modify", line 518, in _smarten_punctuation
File "calibre_plugins.modify_epub.modify", line 504, in smarten_punctuation_for_page
TypeError: a bytes-like object is required, not 'str'
ePub not changed after 0.43 seconds