On Mon, Aug 22, 2016, at 01:35, Steven D'Aprano wrote: > Could somebody (the OP?) please explain what is the purpose of this > proposal, what it does, how it works, and when would people use it?
I think what he wants is a way for a module which uses features (syntactic or otherwise, but I suppose especially syntactic features since this can't as easily be done with a runtime check using existing mechanisms) from a particular python version and which makes no provision to run under earlier versions to fail with a message like "This script requires Python 3.4 or later" rather than a mysterious syntax error or worse a runtime error after the program has been running for some time. -- https://mail.python.org/mailman/listinfo/python-list
