how to copy new object insted of ponting at object python

1>>> import copy
2>>> xs = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
3>>> zs = copy.deepcopy(xs)
4>>> xs[1][0] = 'X'
5>>> xs
6[[1, 2, 3], ['X', 5, 6], [7, 8, 9]]
7>>> zs
8[[1, 2, 3], [4, 5, 6], [7, 8, 9]]