# Bug report ### Bug description: Pre patch ```py from _pydatetime import datetime import sys sys.getsizeof(datetime(1970, 1, 1)) # 152 ``` Post patch ```py from _pydatetime import datetime import sys sys.getsizeof(datetime(1970, 1, 1)) # 120 ``` I had a look round for any other cases of this but couldn't find any just using a simple GitHub search. It might in the future be useful to use https://github.com/ariebovenberg/slotscheck (which I wasn't personally able to figure out how to run on cpython) in CI to prevent things like this in the future. ### CPython versions tested on: CPython main branch ### Operating systems tested on: _No response_ <!-- gh-linked-prs --> ### Linked PRs * gh-109494 <!-- /gh-linked-prs -->