Though I very much like that this exists, and the documentation for contextlib describes its need and use very well[1], I do want to point out that this has always been possible with a tiny bit of recursive glue code like this[2], which works fine even in python 2:

    @contextmanager
    def multi(*cms):
      if len(cms) > 0:
        with cms[0]:
          with multi(*cms[1:]):
            yield
      else:
        yield

    # use with 0..N items, it behaves the same
    with multi(...):
      pass

Prior to finding ExitStack, I've frequently seen people either give up and do something obviously wrong, or try to manually manage their own stack of __enter__ and __exit__ funcs (which works, but exception handling is non-obvious and often loses useful info). Personally I prefer the recursive route, since it very obviously behaves the same as if you wrote the nesting out by hand. It even retains accurate stack traces "naturally", unlike most non-ExitStack tactics I've seen through the years. ExitStack's stack-correcting tactic is... a bit more "interesting"[3], though AFAIK it achieves roughly the same stack trace in the end.

Since ExitStack exists, and is likely more efficient (by how much, I have no idea), it's probably a better choice for most situations. And it's just broadly a bit nicer for things that yield resources.

It's always worth browsing stdlib documentation to find gems like this, there are quite a few neat things in most languages that seem fairly unknown.

[1]: https://docs.python.org/3/library/contextlib.html#supporting...

[2]: https://repl.it/@Groxx/TepidRosybrownLocatorprogram#main.py

[3]: https://github.com/python/cpython/blob/master/Lib/contextlib...