浅拷贝对于创建联合账号有用，如夫妻共同的银行账号。
import copy
unionID = ['username', ['money', 500]]
husband = unionID[:]
wife = copy.copy(unionID)
husband[0] = 'liming'
wife[0] = 'hanmeimei'
print('-----原始账户-----')
print(husband)
print(wife)
print('-----修改husband-----')
husband[1][1] = 600
print(husband)
print(wife)
print('------修改wife------')
wife[1][1] = 1000
print(husband)
print(wife)-----原始账户-----
['liming', ['money', 500]]
['hanmeimei', ['money', 500]]
-----修改husband-----
['liming', ['money', 600]]
['hanmeimei', ['money', 600]]
------修改wife------
['liming', ['money', 1000]]
['hanmeimei', ['money', 1000]]