Getting "IndexError: list index out of range"

from memory_cards import Card
import random


class Game:
    def __init__(self):
        self.size = 4
        self.card_options = ['Sasa', 'Dada', 'Muma', 'Simo', 'Nana', 'Popa', 'Pipi', 'Leee']
        self.columns = ['A', 'B', 'C', 'D']
        self.cards = []
        self.locations = []
        for column in self.columns:
            for num in range(1, self.size + 1):
                print(f'{column}, {num}' )


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

if __name__ == '__main__':
    game = Game()
    game.set_cards()
    for card in game.cards:
        print(card)

class Card:
    def __init__(self, card, location):
        self.card = card
        self.location = location
        self.matched = False

    def __eq__ (self, other):
        return self.card == other.card

    def __str__(self):
        return self.card

if __name__ == '__main__':
    card1 = Card('egg', 'A1')
    card2 = Card('egg', 'B1')
    card3 = Card('horse', 'C1')