When using the generator function to create a 'Code39' barcode, the writer_options={'add_checksum': False} is ignored.
The addition of the check digit happens during the class init which hasn't received the writer_options.
I have a fix for this by moving the check into the render function and adding an instance variable to track when it has been added. (I wasn't sure if the render function could end up being called more than once and didn't want additional check digits adding.
Will create a PR for the fix.