use NULL not 0
merge 3.4
Issue #21875: Remove vestigial references to Classic Mac OS in os module docs.
Issue #21875: Remove vestigial references to Classic Mac OS in os module docs.
asyncio: Oops, restore a removed test
(Merge 3.4) asyncio: Oops, restore a removed test
(Merge 3.4) asyncio, Tulip issue 137: In debug mode, add the traceback where
the coroutine object was created to the "coroutine ... was never yield from"
log