import trio
import gc

class MyException(Exception):
    pass

async def demo():
    async def handle_error():
        try:
            raise MyException
        except MyException as e:
            exceptions.append(e)

    exceptions = []
    try:
        async with trio.open_nursery() as n:
            n.start_soon(handle_error)
        raise ExceptionGroup("errors", exceptions)
    finally:
        del exceptions

async def main():
    exc = None
    try:
        await demo()
    except* MyException as excs:
        exc = excs.exceptions[0]

    assert exc is not None
    print(gc.get_referrers(exc))
    exc.__traceback__.tb_frame.f_locals  # re-materialize f_locals to sync any deletions
    print(gc.get_referrers(exc))

trio.run(main)