#get the nth product of `lists`
def product_by_idx(lists, n):
    result = []
    for seq in reversed(lists):
        n, x = divmod(n, len(seq))
        result.append(seq[x])
    return result[::-1]

#find n such that product(lists, n) == target
def idx_from_product(lists, target):
    n = 0
    for x, seq in zip(target, lists):
        n += seq.index(x)
        n *= len(seq)
    n //= len(lists[-1])
    return n

def product(lists, from_, to_):
    start = idx_from_product(lists, from_)
    end = idx_from_product(lists, to_)
    for n in range(start, 1+end):
        yield product_by_idx(lists, n)

somelists = [
['A', 'b', 'C', '1'],
['d', '2', 'A', '4'],
['c','a', '3', 'g']

]

for item in product(somelists, "A23", "A43"):
    print("".join(item))

"""
Result:
A23
A2g
AAc
AAa
AA3
AAg
A4c
A4a
A43
"""