How do I split long lines in a .vimrc file?

I've got a line in my `.vimrc` that is more than 80 chars long: ``` autocmd FileType python set smartindent cinwords=if,elif,else,for,while,try,except,finally,def,class,with ``` I find this rather annoying, so I want to break it into multiple lines, but I don't know how to do that. I tried `\` since that does the trick in Python and the Bourne shell, but apparently that's not valid syntax in Vim: ``` autocmd FileType python set smartindent \ cinwords=if,elif,else,for,while,try,except,finally,def,class,with ``` gives ``` E492: Not an editor command ``` Can anyone tell me how to split this line? (Bonus points if someone can tell me how to add to `cinwords` instead of resetting it entirely; the only thing I wanted to achieve is add the `with` keyword to it.)