distribute list shuffle python

shuffle.py

a = [a for a in range(20)]
from random import shuffle
shuffle(a)
print a
#[13, 2, 4, 5, 10, 3, 0, 9, 14, 12, 8, 11, 7, 6, 15, 16, 17, 18, 1, 19]
lista = [[],[],[]]
for i,val in enumerate(a):
     lista[i%3].append(val)
 
print lista
#[[13, 5, 0, 12, 7, 16, 1], [2, 10, 9, 8, 6, 17, 19], [4, 3, 14, 11, 15, 18]]