import random
class CardStack:
    def __init__(self, cards):
        self.cards = cards

    def shuffle(self):
        random.shuffle(self.cards)

    def take_card(self):
        if len(self.cards) < 1:
            return None
        card = self.cards[-1]
        self.cards = self.cards[:-1]
        return card

    def place_card(self, card):
        self.cards.append(card)

    def as_str_arr(self):
        return [c.rank + c.suit for c in self.cards]

import random
class CardStack:
    def __init__(self, cards):
        self.cards = cards

    def shuffle(self):
        random.shuffle(self.cards)

    def take_card(self):
        if len(self.cards) < 1:
            return None
        card = self.cards[-1]
        self.cards = self.cards[:-1]
        return card

    def place_card(self, card):
        self.cards.append(card)

    def as_str_arr(self):
        return [c.rank + c.suit for c in self.cards]
