import random


class BlackjackGame:
    """
    This is a class representing a game of blackjack, which includes creating a deck, calculating the value of a hand, and determine the winner based on the hand values of the player and dealer.
    """
    def __init__(self):
        self.deck = self.create_deck()
        self.player_hand = []
        self.dealer_hand = []

    def create_deck(self):
        """
        Create a deck of 52 cards, which stores 52 rondom order poker with the Jokers removed.
        :return: a list of 52 rondom order poker with the Jokers removed, format is ['AS', '2S', ...].
        >>> black_jack_game = BlackjackGame()
        >>> black_jack_game.create_deck()
        ['QD', '9D', 'JC', 'QH', '2S', 'JH', '7D', '6H', '9S', '5C', '7H', 'QS', '5H',
        '6C', '7C', '3D', '10C', 'AD', '4C', '5D', 'AH', '2D', 'QC', 'KH', '9C', '9H',
        '4H', 'JS', '6S', '8H', '8C', '4S', '3H', '10H', '7S', '6D', '3C', 'KC', '3S',
        '2H', '10D', 'KS', '4D', 'AC', '10S', '2C', 'KD', '5S', 'JD', '8S', 'AS', '8D']
        """

        deck = []
        suits = ['S', 'C', 'D', 'H']
        ranks = ['A', '2', '3', '4', '5', '6', '7', '8', '9', '10', 'J', 'Q', 'K']
        for suit in suits:
            for rank in ranks:
                deck.append(rank + suit)
        random.shuffle(deck)
        return deck

    def check_winner(self, player_hand, dealer_hand):
        """
        Determines the winner of a game by comparing the hand values of the player and dealer.
        rule:
        If both players have hand values that are equal to or less than 21, the winner is the one whose hand value is closer to 21.
        Otherwise, the winner is the one with the lower hand value.
        :param player_hand: list
        :param dealer_hand: list
        :return: the result of the game, only two certain str: 'Dealer wins' or 'Player wins'
        >>> black_jack_game.check_winner(['QD', '9D', 'JC', 'QH', 'AS'], ['QD', '9D', 'JC', 'QH', '2S'])
        'Player wins'
        """

        player_value = self.calculate_hand_value(player_hand)
        dealer_value = self.calculate_hand_value(dealer_hand)
        if player_value > 21 and dealer_value > 21:
            if player_value <= dealer_value:
                return 'Player wins'
            else:
                return 'Dealer wins'
        elif player_value > 21:
            return 'Dealer wins'
        elif dealer_value > 21:
            return 'Player wins'
        else:
            if player_value <= dealer_value:
                return 'Dealer wins'
            else:
                return 'Player wins'

Method:
def calculate_hand_value(self, hand):
        value = 0
        num_aces = 0
        for card in hand:
            rank = card[:-1]
            if rank.isdigit():
                value += int(rank)
            elif rank in ['J', 'Q', 'K']:
                value += 10
            elif rank == 'A':
                value += 11
                num_aces += 1
        while value > 21 and num_aces > 0:
            value -= 10
            num_aces -= 1
        return value

Summary: Calculate the value of the poker cards stored in hand list according to the rules of the Blackjack Game. If the card is a digit, its value is added to the total hand value. Value of J, Q, or K is 10, while Aces are worth 11. If the total hand value exceeds 21 and there are Aces present, one Ace is treated as having a value of 1 instead of 11, until the hand value is less than or equal to 21, or all Aces have been counted as value of 1.