[issue40114] support maxsize argument for lru_cache's user_function option

[brendon zhang]

Change by brendon zhang <brendon-zhang at hotmail.com>:


----------
keywords: +patch
pull_requests: +18588
stage:  -> patch review
pull_request: https://github.com/python/cpython/pull/19226

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue40114>
_______________________________________