I also don't know Twine, so I checked its documentation. It says:
-u USERNAME, --username USERNAME
The username to authenticate to the repository
(package index) as. (Can also be set via
TWINE_USERNAME environment variable.)
-p PASSWORD, --password PASSWORD
The password to authenticate to the repository
(package index) with. (Can also be set via
TWINE_PASSWORD environment variable.)
So you can use environment variables to provide the credentials, which means you can use the instructions from my previous mail.