IndexError: list index out of range Python OOP Basics

Traceback (most recent call last):
  File "game.py", line 94, in <module>
    game.start_game()
  File "game.py", line 82, in start_game
    if self.check_match(guess1, guess2):
  File "game.py", line 51, in check_match
    if cards[0] == cards[1]:
IndexError: list index out of range

class Game:
    def __init__(self):
        self.size = 4
        self.card_options = ['Add', 'Boo', 'Cat', 'Dev',  'Egg', 'Far', 'Gum', 'Hut']
        self.columns = ['A', 'B', 'C', 'D']
        self.cards = []
        self.locations = []
        for column in self.columns:
            for num in range(1, self.size + 1):
                location = f'{column}{num}'
                self.locations.append(location)

    def set_cards(self):
        used_locations = []
        for card in self.card_options:
            for i in range(2):
                random_location = random.choice(list(set(self.locations) - set(used_locations)))
                used_locations.append(random_location)
                game_card = Card(card, random_location)
                self.cards.append(game_card)

    def create_row(self, num):
        row = []
        for column in self.columns:
            for card in self.cards:
                if card.location == f'{column}{num}':
                    if card.matched:
                        row.append(str(card))
                    else:
                        row.append('   ')
            return row

    def create_grid(self):
        header = ' |  ' + '  |  '.join(self.columns) + '  |'
        print(header)
        for row in range(1, (self.size + 1)):
            print_row = f'{row}| '
            get_row = self.create_row(row)
            print_row += ' | '.join(get_row) + ' |'
            print(print_row)

    def check_match(self, loc1, loc2):
        cards = []
        for card in self.cards:
            if card.location == loc1 or card.location == loc2:
                cards.append(card)
            if cards[0] == cards[1]:
                cards[0].matched = True
                cards[1].matched = True
                return True
            else:
                for card in cards:
                    print(f'{card.location}: {card}')
                return False

    def check_win(self):
        for card in self.cards:
            if card.matched is False:
                return False
        return True

    def check_location(self, time):
        while True:
            guess = input(f"What's the location of your {time} card? ")
            if guess.upper() in self.locations:
                return guess.upper()
            else:
                print("That's not a valid location. Location should be column name then row name like A1.")

    def start_game(self):
        game_running = True
        print("Memory Game")
        self.set_cards()
        while game_running:
            self.create_grid()
            guess1 = self.check_location("first")
            guess2 = self.check_location("second")
            if self.check_match(guess1, guess2):
                if self.check_win():
                    print("Congrats, you win")
                    self.create_grid()
                    game_running = False
            else:
                input('those cards are not a match.  Press enter to continue')

        print("Game Over")

if __name__ == '__main__':
    game = Game()
    game.start_game()