这段程序会输出什么？

这段程序会输出什么？

items = ["mouse"]
alias = items
snapshot = items.copy()
alias.append("cable")
items = snapshot

print(alias)
print(items)
print(alias is items)

1. ['mouse', 'cable'] ['mouse'] False
2. ['mouse', 'cable'] ['mouse', 'cable'] True
3. ['mouse'] ['mouse'] False
4. 程序在赋值时抛出 TypeError。