Fix python literals command example

[rana-ahmed]

In my day to day deployment I use yasha to render config file. But when I try to pass comma seperated string I found that, comma seperated string can be passed only in following way.

[kblomqvist]

I must be missing something. Doesn't your example evaluate as '"foo,bar,baz"' when read as an argument? Don't you want it to be either 'foo,bar,baz' or "foo,bar,baz". The current readme-example gives you the latter.