How to generate a permutation of list of lists in python -

i have list of lists say

[[2, 4, 6], [2, 6, 10], [2, 12, 22], [4, 6, 8], [4, 8, 12], [6, 8, 10], [8, 10, 12], [8, 15, 22], [10, 11, 12]] 

how generate combination of lists given length?

for example if given length 3

then need combinations of 3 list element scenarios given list of list.

example :

[2, 4, 6], [2, 6, 10], [2, 12, 22] 

or

[2, 4, 6], [8, 10, 12], [10, 11, 12] ... ... , forth 

and if given length 2 should like

[2, 4, 6], [2, 6, 10] 

or

[6, 8, 10], [8, 10, 12] ... ... , forth 

i dont want permutation of elements inside lists want permutation of lists itself.

there 2 options here. first use itertools.permutations. give every permutation (i.e: [1,2] , [2,1] would not same)

import itertools  lists = [[2, 4, 6], [2, 6, 10], [2, 12, 22], [4, 6, 8], [4, 8, 12], [6, 8, 10], [8, 10, 12], [8, 15, 22], [10, 11, 12]] n = 3  perm in itertools.permutations(lists, n):     print(perm) 

if want unique groupings, no duplicates , use itertools.combinations (i.e: [1,2] , [2,1] would same).

for comb in itertools.combinations(lists, n):     print(comb)