get_page.py

def get_page(page_id:int) -> Page:
    
    # Check if the page is available in the cache
    page = cache.get_page(page_id)
    
    # if the page is retrieved from the main memory
    # return the page.
    if page:
        return page
    
    # retrieve the page from the disk
    page = disk.get_page(page_id)
    
    # put the page in the cache,
    # if the cache is full, evict a page which is
    # least recently used.
    if cache.is_full():
        cache.evict_page()
    
    # put the page in the cache
    cache.put_page(page)
    
    # return the pages
    return page