from itertools import product
lists = [[1, 2, 3], [4, 5, 6], [7, 8]]
print(list(product(*lists)))
'''
run:
[(1, 4, 7), (1, 4, 8), (1, 5, 7), (1, 5, 8), (1, 6, 7), (1, 6, 8),
(2, 4, 7), (2, 4,8), (2, 5, 7), (2, 5, 8), (2, 6, 7), (2, 6, 8),
(3, 4, 7), (3, 4, 8), (3, 5, 7), (3,5, 8), (3, 6, 7), (3, 6, 8)]
'''