adding values from a csv column and getting the mean. beginner help

[Chris Angelico]

On Thu, Dec 12, 2013 at 6:41 AM, Mark Lawrence <breamoreboy at yahoo.co.uk> wrote:
>> Square brackets in a usage description often mean "optional". You may
>> want to be careful of that. There's no really good solution though.
>
> There is, https://pypi.python.org/pypi/docopt/0.6.1 :)

That appears to use <x> for a mandatory argument x, which is then
slightly ambiguous with shell redirection. But that's the best
notation I've ever seen for distinguishing mandatory args from fixed
keywords.

CrisA