即使仅保存在不同的对象上，更改也会出现在主对象上？
A dict:
transportation = {"car":"ford", "coche":"fiat"}
The changes:
x = transportation.setdefault("carro", "BMW")
Output of the object where changes were stored(x):
BMW
Output of the original dict:
{"car":"ford", "coche":"fiat", "carro", "BMW"}