[python] List Combine

import itertools

a = [ 1 , 1 ]
b = [ 2, 2 , 2]
c = [ 3 , 3 ]

result_A = a + b + c
result_B = list(itertools.chain(a,b,c))
a.extend(b)
a.extend(c)
result_C = a


print result_A
print result_B
print result_C