I added a comment to the top answer here but couldn't get the code to format correctly. I made sure I was entering the 4 spaces. The comment was only editable for 5 minutes and it now appears to late to fix it. What should I do? The comment is important in explaining why I unaccepted the answer.
The 4-space indentation doesn't work in comments. Comments have a very dumbed down version of the full markdown that's available in posts.
The best you can do is put the ticks (``) around your code, using the key in the upper left near the numbers. This will highlight the code. You will not be able to do full indentation and stuff.