Method modify

crates/stdlib/src/select.rs:467–479

(
                &self,
                Fildes(fd): Fildes,
                eventmask: EventMask,
                vm: &VirtualMachine,
            )

            #[pymethod]
            fn modify(
                &self,
                Fildes(fd): Fildes,
                eventmask: EventMask,
                vm: &VirtualMachine,
            ) -> PyResult<()> {
                let mut fds = self.fds.lock();
                // CPython raises KeyError if fd is not registered, match that behavior
                let pfd = get_fd_mut(&mut fds, fd)
                    .ok_or_else(|| vm.new_key_error(vm.ctx.new_int(fd).into()))?;
                pfd.events = eventmask.0;
                Ok(())
            }

            #[pymethod]
            fn unregister(&self, Fildes(fd): Fildes, vm: &VirtualMachine) -> PyResult<()> {