You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: lib.rs
    path of file: ./repos/Sophon/libs/device-tree/src
    
    the code of the file until where you have to start completion: #![no_std]

extern crate alloc;

use core::ops::Range;

use alloc::vec;
use alloc::vec::Vec;
use fdt_rs::base::*;
use fdt_rs::index::*;
use fdt_rs::prelude::*;
use memory::address::{Address, P};

pub struct DeviceTree<'buf, 'index> {
    _buf: &'buf [u8],
    _index_buf: Vec<u8>,
    index: DevTreeIndex<'index, 'buf>,
}

impl<'buf, 'index> DeviceTree<'buf, 'index> {
    pub fn new(buf: &'buf [u8]) -> Option<Self> {
        let devtree = unsafe { DevTree::new(buf) }.ok()?;
   
    
    pub fn regs<'x>(&'x self) -> Option<impl Iterator<Item = Range<Address<P>>> + 'x> {
        let CellSizes {
            address_cells,
            size_cells,
        } = self.parent().unwrap().cell_sizes();
        let prop = self.node.props().find(|p| p.name() == Ok("reg"))?;
        let mut buf = prop.raw();
        Some(core::iter::from_fn(move || {
            if buf.is_empty() {
                return None;
            }
            let addr = match address_cells {
                1 => Address::<P>::new(Self::read_u32(&mut buf) as usize),
                2 => Address::<P>::new(Self::read_u64(&mut buf) as usize),
                _ => unreachable!(),
            };
            let size = match size_cells {
                1 => Self::read_u32(&mut buf) as usize,
                2 => Self::read_u64(&mut buf) as usize,
                _ => unreachable!(),
            };
            Some(addr..addr + size)
        }))
    }