The following two lines work in Mojave, but flag an error in Catalina:
>>> from AppKit import NSSavePanel
>>> panel = NSSavePanel.savePanel()
The error is:
2019-10-29 18:24:22.275 Python[6577:255233] *** Assertion failure in +[NSServiceViewController currentAppIsViewService], /BuildRoot/Library/Caches/com.apple.xbs/Sources/ViewBridge/ViewBridge-462/NSViewService.m:140
2019-10-29 18:24:22.275 Python[6577:255233] *** Assertion failure in +[NSServiceViewController currentAppIsViewService], /BuildRoot/Library/Caches/com.apple.xbs/Sources/ViewBridge/ViewBridge-462/NSViewService.m:140
2019-10-29 18:24:22.342 Python[6577:255347] +[NSXPCSharedListener endpointForReply:withListenerName:]: an error occurred while attempting to obtain endpoint for listener 'com.apple.view-bridge': Connection interrupted
This is with PyObjC 5.2. I get the same error (or not) in python 2.7 and python 3.7.
