generating tuples using n-lists with itertools.product

Question

How can I use itertools.product function if I don't know the number of the lists? I have list and it has lists inside of it.

Like,

lis = [[1,2,3],[6,7,8],[2,4,5]]

Normally I need to do,

product([1,2,3],[6,7,8],[2,4,5])

How do I do that if the input is a list like in the example?

Answer 1

Try the following:
product(*lis)
It's called argument unpacking.
Short note: you can use argument unpacking with named parameters also, with double star:

def simpleSum(a=1,b=2):
    return a + b
simpleSum(**{'a':1,'b':2}) # returns 3