proxy pattern | Python Fiddle

class SensitiveInfo:
    def __init__(self):
        self.users = ['nick', 'tom', 'ben', 'mike']
        
    def read(self):
        print('There are {} users: {}'.format(len(self.users), ' '.join(self.users)))
              
    def add(self, user):
        self.users.append(user)
        print('Added user {}'.format(user))

class Info:
    def __init__(self):
        self.protected = SensitiveInfo()
        self.secret = '0xdeadbeef'
        
    def read(self):
        self.protected.read()
        
    def add(self, user):
        sec = input('what is the secret? ')
        if sec == self.secret:
            self.protected.add(user) 
        else: 
            print('That\'s wrong!')

def main():
    info = Info()
    while True:
        print('1. read list |==| 2. add user |==| 3. quit')
        key = input('choose option: ')
        if key == 1:
            info.read()
        elif key == 2:
            name = input('choose username: ')
            info.add(name)
        elif key == 3:
            exit()
        else:
            print('unknown option: {}'.format(key))

if __name__ == '__main__':
    main()

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