Mini Shell

import sys

# Override theSystemPath so it throws KeyError on gi.pygtkcompat:
from twisted.python import modules
from twisted.python.reflect import requireModule

modules.theSystemPath = modules.PythonPath([], moduleDict={})

# Now, when we import gireactor it shouldn't use pygtkcompat, and should
# instead prevent gobject from being importable:
gireactor = requireModule("twisted.internet.gireactor")
for name in gireactor._PYGTK_MODULES:
    if sys.modules[name] is not None:
        sys.stdout.write(
            "failure, sys.modules[%r] is %r, instead of None"
            % (name, sys.modules["gobject"])
        )
        sys.exit(0)

try:
    import gobject  # type: ignore[import]
except ImportError:
    sys.stdout.write("success")
else:
    sys.stdout.write(f"failure: {gobject.__path__} was imported")