深拷贝

import copy

a = {
    'key1': 1,
    'key2': [1, 2, 3],
    'key3': {'subkey': 'value'},
}

b = copy.deepcopy(a)

# 验证深拷贝
a['key2'].append(4)
a['key3']['subkey'] = 'new value'

print("a", a)
print("b", b)