When translating interpolated strings, you want to use named values so that they show up in the string and can be understood by the translator when they are working on the file.

Example: 
        
    message=_("User '{user}' has successfully been {action}.").format(
        user=user.raw_username,
        action=_("Un-Archived") if user.is_active else _("Archived"),
    )

This ends up in the translations file as:

`msgid "User '{user}' has successfully been {action}."`