I'm not sure what that is supposed to mean in this context. Testing for "is not None" is more explicit and avoids the trap being discussed. I don't know how the second sentence applies, maybe "if timeval:" is simpler?

BTW, do you know the original author of the Zen of Python has posted to this very dicussion (while also being the orginal author of said module):

https://mail.python.org/pipermail/python-ideas/2014-March/02... https://mail.python.org/pipermail/python-ideas/2014-March/02...