SabreSwap is primarily written in rust currently, there is just a small component of the pass which takes the python objects representing the DAGCircuit and backend constraints and builds rust objects from those, then after the rust code finishes another piece uses the return from rust to rebuild the dagcircuit with the extra swaps inserted in python. Once #11721 is implemented we can remove this python space component and build the dagcircuit directly in rust and never need any python space component to the pass.