I admit I haven't paid enough attention to the py3 switch on sage-devel, but this still surprised me, based on the wording at https://wiki.sagemath.org/Python3-compatible%20code I suppose that when the py3 switch for default is thrown, we should make sure to have a special request for testing from the whole community to make sure we have no weird regressions on py2 until after 9.1 (or that is what the Wiki currently says).
$ ./sage -v SageMath version 9.0.beta4, Release Date: 2019-11-02 $ ./sage -python Python 2.7.15 (default, Nov 6 2019, 12:35:23) [GCC 4.2.1 Compatible Apple LLVM 7.3.0 (clang-703.0.31)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> -- You received this message because you are subscribed to the Google Groups "sage-release" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-release+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-release/e305effd-1f7f-4ff7-92ef-f6ce3d79ba7d%40googlegroups.com.