Before the explanation of #3, I'll help you with the "invalid syntax" error. You need to add a colon (
in the end, right after "john" It will fix it. Look at my #4 in my last post.
To the #3.
Many programming languages (C, C++, C#, Java, Visual Basic, many LISP-dialects, etc.) and also Python, of course, uses special techniques to identify variables, strings, characters. It's different from language to language, but usually you're using single-quotes for characters, double-quotes for strings and nothing for variables. Try to pick up some tutorial, it will clear it up for you - much better than I tried - and you'll understand.