I used to write Python scripts and have the option parsing go something like this…

if __name__ == “__main__”:
import sys, getopt

opts, args = getopt.getopt(sys.argv[1:], ‘h’, [‘help’])

for opt, val in opts:
if opt in (‘-h’, ‘–help’):
usage(sys.argv)
sys.exit(1) # Exit to shell with non-zero result

And then I finally started writing tests for my code, at which point I decided
I need to [`raise SystemExit(1)`][exception] rather than `sys.exit(1)` because I imagined
[Python’s unittest module][unittest] would get bypassed whenever my code called
`sys.exit(1)`.

Except of course I was wrong. [`sys.exit` throws `SystemExit` in turn][sysexit],
so it comes to the same thing from the point of view of `unittest`. Failing to read
documentation is a very bad habit.

But I prefer throwing the exception myself. You don’t have to `import sys` if you
don’t need it, and *it feels prettier* (if I had more Python experience I might say *more Python-ic*).

I used to [smoke, drink and dance the hoochie-coo][saved] too.

[unittest]: http://docs.python.org/library/unittest.html
[sysexit]: http://docs.python.org/library/sys.html#sys.exit
[exception]: http://docs.python.org/library/exceptions.html#exceptions.SystemExit
[saved]: http://www.google.co.uk/search?q=lavern%20baker%20saved