Owl

L1 = [2] # Creates object 2(type int) and put it in L1(list) at [0] index
L2 = [L1, L1] # Put reference links in L2(list) to L1(list) at [0] index and [1] index]
print 'L2 =', L2 # Prints L2(list)
L1[0] = 3 # Creates object 3(type int) and re-assign [0] index in L1(list) to it
print 'L2 =', L2 # Prints L2(list)

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# L2(list) changing because it contain 2 reference links to L1(list) not values
# one refernce at [0] index another one at [1] index
# to avoid mutating u should assign value of L1 to L2 at index's [0] and [1]
# L2 = [L1[0], L1[0]]
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