[tzot]

There's `contextlib.closing` for objects that do not support the context manager protocol and they should be closed.

And then one can simulate defer in the spirit of the `atexit` module with a single context manager (say `finalizer`), defined only once, which could be used as:

    with finalizer() as defer:
        ...
        req = requests.get('https://w3.org/')
        defer(req.close)  # just like contextlib.closing
        ...
        a_dict['key'] = value
        defer(a_dict.__delitem__, 'key')
        ...
        defer(print, "all defers ran", file=sys.stderr)
        ...

The `__call__` of finalizer adds callables with their *args and **kwargs to a fifo or a stack, and its `__exit__` will call them in sequence.