Re: [Python-ideas] Avoiding nested for try..finally: atexit for functions?

Why introduce an error handler at all? If you want to handle exceptions inside the with statement, an explicit try-except block would be both more convenient (you don't need an extra function definition) and more flexible (you can use - say - 'except ValueError:' to just catch some exceptions). To give an example, I'd really prefer

with CleanupManager() as cleanup:
    try:
        # do stuff
    except ValueError:
        # handle exception