I'll join the chorus recommending against inventing the wheel, unless you're doing that to learn SAML in which case I say more power to you. You should look into the existing work done by Roland Hedberg, SUNET, and others on pysaml2, which is now part of the IdentityPython project:
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.
https://idpy.org/
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.