control structures and functions when printing the list or the filenamesprint the item numbers using field width of if there are less than ten itemsof if there are less than itemsand of otherwise keep the items in case-insensitive alphabetical orderand keep track of whether the list is "dirty(has unsaved changesoffer the "saveoption only if the list is dirty and ask the user whether they want to save unsaved changes when they quit only if the list is dirty adding or deleting an item will make the list dirtysaving the list will make it clean again model solution is provided in listkeeper pyit is less than lines of code