bulls game

import random

x1 = random.choice(range(1, 10))
x2 = random.choice([x for x in range(0,10) if x not in [x1]])
x3 = random.choice([x for x in range(0,10) if x not in [x1, x2]])
x4 = random.choice([x for x in range(0,10) if x not in [x1, x2, x3]])

number = '%s%s%s%s' % (x1, x2, x3, x4)

print(number)

while True:
    user_number = input('введите загаданное число: ').strip()
    if len(set(list(user_number))) < 4:
        print('вводить можно только 4-х значные числа с неповторяющимися цифрами!')
        continue
    if user_number == number:
        print('Вы выиграли!')
        break
    cows, bulls = 0, 0
    cows = len(set(list(number)).intersection(list(user_number)))
    bulls = len([x for x in zip(list(number), list(user_number)) if x[0] == x[1]])
    print('коров %s быков %s' % (cows, bulls))