Are there any FOSS Python Single-Sign-on Servers?

[Phillip B Oldham]

Are there any FOSS Python Single-Sign-on Servers?

We're looking to centralise the sign-on for our numerous "internal"
webapps (across multiple servers, languages, and domains) to speed
user management and application development.

I've searched around but can only seem to find OpenID servers, which
will probably be too "open" for our needs. Coding one up would
possibly take more time than we have, and we'd prefer something
maintained externally to cut dev costs.