Method register

crates/stdlib/src/select.rs:453–464

(
                &self,
                Fildes(fd): Fildes,
                eventmask: OptionalArg<EventMask>,
            )

        impl PyPoll {
            #[pymethod]
            fn register(
                &self,
                Fildes(fd): Fildes,
                eventmask: OptionalArg<EventMask>,
            ) -> PyResult<()> {
                let mask = match eventmask {
                    OptionalArg::Present(event_mask) => event_mask.0,
                    OptionalArg::Missing => DEFAULT_EVENTS,
                };
                insert_fd(&mut self.fds.lock(), fd, mask);
                Ok(())
            }

            #[pymethod]
            fn modify(