@property
    def safe_num(self):
        card_length = len(self.number)
        stars = '*' * (card_length - 4)
        return '{0}{1}'.format(stars, self.number[-4:])
outputs the card number with *'s, only exposing last four digits of card number
dataset/ETHPy150Open abunsen/Paython/paython/lib/cc.py/CreditCard.safe_num