Overriding DateTime.now() at a local context without using a third party lib in python

Question

I am looking into ways for overriding datetime.now() or similar method in python. Ideally I would like to override on a per request basis or control cases where I want to freeze the datetime.now() and not necessarily all calls to datetime.now(). From what I understand, libraries like freezegun freeze all calls to datetime.now().

• I want to implement a new version of Datettime, say Datettime.override.
• Have two variables called frozenTime which has a frozen time value.
• Implement datetime.provider(frozenTime) which returns either return default datetime impl or return datettime.override if frozenTime > 0