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: mmu.rs
    path of file: ./repos/rust-raspberrypi-OS-tutorials/17_kernel_symbols/kernel/src/bsp/raspberrypi/memory
    
    the code of the file until where you have to start completion: // SPDX-License-Identifier: MIT OR Apache-2.0
//
// Copyright (c) 2018-2023 Andre Richter <andre.o.richter@gmail.com>

//! BSP Memory Management Unit.

use crate
    
fn virt_code_region() -> MemoryRegion<Virtual> {
    let num_pages = size_to_num_pages(super::code_size());

    let start_page_addr = super::virt_code_start();
    let end_exclusive_page_addr = start_page_addr.checked_offset(num_pages as isize).unwrap();

    MemoryRegion::new(start_page_addr, end_exclusive_page_addr)
}