For this use case, they'd also need to configure JAAS.
I've been thinking of writing my own SAML IdP in Python (since I have plenty of experience with the language) and I'm not naive to the various security things that can go wrong, but I'm no expert cryptographer either.
https://github.com/IdentityPython
That said, I can't think of anyone using pysaml2 to implement identity providers aside from SATOSA, an IdP proxy. Nearly everyone I know runs either Shibboleth or SimpleSAMLphp. I recommend you run Shibboleth because there's a whole litany of interoperability issues you _won't_ encounter if you do. (The same goes for SimpleSAMLphp, but I have less experience with it.)
The IdentityPython and Shibboleth projects have a lot of overlap in terms of membership, and if you want to meet them and connect to the research and education side of the federated IdM community, which drives a lot of the open source work, you should come to the Internet2 Technology Exchange this year and stay for ACAMP. It's a super smart bunch of people. You'll learn a lot.
If you're doing that for a small company, maybe try to get a Microsoft active directory instead. It's a lot easier to setup and maintain and everything does their best to integrate with it.
You don't have to be, as you would not implement any cryptographic algorithms (ciphers, hash methods) yourself. Solid experience with software security in general is a requirement of course.