`sorted()` does shallow copy instead of deep copy

[hyperkai]

Bug report

Bug description:

sorted() does shallow copy instead of deep copy as shown below. *It's problematic:

originlist = ['apple', 'banana', ['kiwi', 'cherry']]

newlist = sorted(originlist, key=len)
print(newlist)    # [['kiwi', 'cherry'], 'apple', 'banana']

newlist[0][1] = 'CHERRY'
newlist[2] = 'BANANA'

print(newlist)    # [['kiwi', 'CHERRY'], 'apple', 'BANANA']
print(originlist) # ['apple', 'banana', ['kiwi', 'CHERRY']]
                                               # ↑↑↑↑↑↑↑↑

CPython versions tested on:

3.12

Operating systems tested on:

Windows

[JelleZijlstra]

This is working as intended; doing a deep copy would be unintuitive in many cases and would break a lot of working code.