That hopefully prevents the error "codecov failed with exit code 255".

This condition has been checked at the beginning of the function.

Noticed this in the code coverage report.

It's not really about security

Use 'elif' instead of 'if' to avoid wrong self.result when
self.state is 'off'.

We need unit-tests for the engine checking the correctness: #79

These objects should be compared for identity with None using 'is' operator.

Part IV, sys.exit()

Part III, strings

Part II, assert()

Part I, print()

Thanks to @izh1979

Thanks to @izh1979

Linus about AIO: https://lwn.net/Articles/671657/
LWN: Fixing asynchronous I/O, again: https://lwn.net/Articles/671649/

See https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b30a43ac7132cdda833ac4b13dd1ebd35ace14b7

Dave Airlie:
There was a nouveau DDX that relied on legacy context ioctls to work,
but we fixed it years ago, give distros that have a modern DDX the
option to break the uAPI and close the mess of holes that legacy
context support is.

Ready for release 0.6.1.

No functional changes