python get unique pairs from two lists
# note: this works for two list only
from itertools import product
l1 = [1,2,3]
l2 = [4,5,6] # works if the second list has a different lenght too
product(l1, l2)
>>> <itertools.product object at 0x7f1539c89af0>
list(product(l1, l2))
>>> [(1, 4), (1, 5), (1, 6),
(2, 4), (2, 5), (2, 6),
(3, 4), (3, 5), (3, 6)]