the python is just turning templates into crates for each svd file. the work of building a pac is inside the build.rs that is generated from each template.
and that build.rs uses svd2rust and form to transform the svd into a PAC crate.

here's the same steps, in a shell script (which we could do for rp2040 since there was only one svd).
lines 19 through 33 are really all you need. patch broken svd, convert to lib.rs, break apart lib.rs, cargo fmt.
https://github.com/rp-rs/rp2040-pac/blob/89e78ff078d88cfbbad91bd5aa4eb4ac79a57dab/update.sh#L28