Barcode Generator

start_num = int(input())
final_num = int(input())

for a in range(start_num // 1000, final_num // 1000 + 1):
    for b in range(start_num // 100 % 10, final_num // 100 % 10 + 1):
        for c in range(start_num // 10 % 10, final_num // 10 % 10 + 1):
            for d in range(start_num % 10, final_num % 10 + 1):
                if a % 2 == 1 and b % 2 == 1 and c % 2 == 1 and d % 2 == 1:
                    print(f'{a}{b}{c}{d}', end=' ')

ИЛИ:

start_num = input()
final_num = input()

for a in range(int(start_num[0]), int(final_num[0]) + 1):
    for b in range(int(start_num[1]), int(final_num[1]) + 1):
        for c in range(int(start_num[2]), int(final_num[2]) + 1):
            for d in range(int(start_num[3]), int(final_num[3]) + 1):
                if a % 2 == 1 and b % 2 == 1 and c % 2 == 1 and d % 2 == 1:
                    print(f'{a}{b}{c}{d}', end= ' ')