powerful class tool conceptssuch as decorators and metaclassesalong with python' many introspection toolsthey allow us to write code that augments and manages classes in structured and maintainable ways step (final)storing objects in database at this pointour work is almost complete we now have two-module system that not only implements our original design goals for representing peoplebut also provides general attribute display tool we can use in other programs in the future by coding functions and classes in module fileswe've ensured that they naturally support reuse and by coding our software as classeswe've ensured that it naturally supports extension although our classes work as plannedthoughthe objects they create are not real database records that isif we kill pythonour instances will disappear--they're transient objects in memory and are not stored in more permanent medium like fileso they won' be available in future program runs it turns out that it' easy to make instance objects more permanentwith python feature called object persistence-making objects live on after the program that creates them exits as final step in this tutoriallet' make our objects permanent pickles and shelves object persistence is implemented by three standard library modulesavailable in every pythonpickle serializes arbitrary python objects to and from string of bytes dbm (named anydbm in python ximplements an access-by-key filesystem for storing strings shelve uses the other two modules to store python objects on file by key we met these modules very briefly in when we studied file basics they provide powerful data storage options although we can' do them complete justice in this tutorial or bookthey are simple enough that brief introduction is enough to get you started the pickle module the pickle module is sort of super-general object formatting and deformatting toolgiven nearly arbitrary python object in memoryit' clever enough to convert the object to string of byteswhich it can use later to reconstruct the original object in memory the pickle module can handle almost any object you can create--listsdicstep (final)storing objects in database