I have a question about PEP 525 (Asynchronous Generators) which I'm sure has a simple answer, but I didn't see it in the PEP or final discussion: https://mail.python.org/pipermail/python-dev/2016-September/146265.html Basically, why is the API such that loop.shutdown_asyncgens() must be called manually? For example, why can't it be called automatically as part of close(), which seems like it would be a friendlier API and more helpful to the common case? I was trying asynchronous iterators in my code and getting the following error: Exception ignored in: <generator object Queue.get at 0x7f950a667678> Traceback (most recent call last): File "/usr/local/lib/python3.6/asyncio/queues.py", line 169, in get getter.cancel() # Just in case getter is not done yet. File "/usr/local/lib/python3.6/asyncio/base_events.py", line 574, in call_soon self._check_closed() File "/usr/local/lib/python3.6/asyncio/base_events.py", line 357, in _check_closed raise RuntimeError('Event loop is closed') RuntimeError: Event loop is closed Calling loop.shutdown_asyncgens() made the error go away, but it seems a little obscure that by adding an asynchronous iterator somewhere in your code, you have to remember to check that that line is present before loop.close() is called (and the exception message doesn't provide a good hint). Is there any disadvantage to always calling loop.shutdown_asyncgens() (i.e. even if it's not needed)? And why might someone need to call it at a different time? Thanks, --Chris