Message4661

Have you tried using PySystemState#shadow? This is for the purpose of
working around the use of statics, specifically builtins, warnoptions,
and platform. (Unfortunately we won't be able to make breaking API
changes in modules like PySystemState until 3.x.)

PySystemState.modules is an instance variable, so that should also work
for you.

You can see a moderate exercise of this is in test_sys_jy.py,
specifically the test case ShadowingTest.

Note that this bug is related to #471481, #1868602, and #607391.