It used to be a whitelist approach allowed only alphabet and a part of symbols.
but most doujinshi's names include Japanese 2-byte characters and these was rejected.
so it is using blacklist approach now.
- if filename include forbidden characters (\'/:,;*?"<>|) ,it replace space character(' ').
+ if filename include forbidden characters (\'/:,;*?"<>|) ,it replace space character(' ').
"""
# maybe you can use `--format` to select a suitable filename
ban_chars = '\\\'/:,;*?"<>|\t'