Function register_rust_extractor 

pub fn register_rust_extractor<T>() -> Result<(), Error>
where
    T: CustomDataTrait + for<'a, 'py> FromPyObject<'a, 'py> + Send + Sync + 'static,

Registers a Rust custom data type for Python extraction. Call once per type at module load (e.g. in the persistence PyO3 module). Uses register_rust_extractor_factory with a factory that builds the extractor for T.

Errors

Returns an error if the type name is already registered.