there' simple analysisnow let' proceed with design we're obviously going to need user class that stores the username and an encrypted password this class will also allow user to log in by checking whether supplied password is valid we probably won' need permission classas those can just be strings mapped to list of users using dictionary we should have central authenticator class that handles user management and logging in or out the last piece of the puzzle is an authorizor class that deals with permissions and checking whether user can perform an activity we'll provide single instance of each of these classes in the auth module so that other modules can use this central mechanism for all their authentication and authorization needs of courseif they want to instantiate private instances of these classesfor non-central authorization activitiesthey are free to do so we'll also be defining several exceptions as we go along we'll start with special authexception base class that accepts username and optional user object as parametersmost of our self-defined exceptions will inherit from this one let' build the user class firstit seems simple enough new user can be initialized with username and password the password will be stored encrypted to reduce the chances of its being stolen we'll also need check_password method to test whether supplied password is the correct one here is the class in fullimport hashlib class userdef __init__(selfusernamepassword)'''create new user object the password will be encrypted before storing ''self username username self password self _encrypt_pw(passwordself is_logged_in false def _encrypt_pw(selfpassword)'''encrypt the password with the username and return the sha digest ''hash_string (self username passwordhash_string hash_string encode("utf "return hashlib sha (hash_stringhexdigest(def check_password(selfpassword)'''return true if the password is valid for this userfalse otherwise ''encrypted self _encrypt_pw(passwordreturn encrypted =self password