I use parentheses appended to title, as in:
Learning Python (4th ed)
When appended to title after the initial Add of the book, parentheses persist in title_sort, and title in the booklist is sorted per entire title_sort including parentheses and their content. I use the tweak: title_series_sorting = 'strictly_alphabetic'.
When Adding books per the regular expression I use, any parentheses and their content are stripped out. That is per regular expression, and (I assume) not any explicit calibre behavior outside the regular expression. The regular expression I use for Adding books is from the Quick Preferences plugin:
Code:
^(?P<author>((?!\s-\s).)+)\s-\s(?:(?:\[\s*)?(?P<series>.+)\s(?P<series_index>[\d\.]+)(?:\s*\])?\s-\s)?(?P<title>[^(]+)(?:\(.*\))?