The code as it was at 18 min in the Video is not working for me 
I'm getting an error. 
Only after adding the code from the provided scripts did I get the expected result . In the video we learned how to catch the 'no camera option', but the error I got about the string enum I don't understand
As Martin stated it is because there's no underscore between the words. Also if you look at the error it gives all the acceptable parameters. The error is confusing in the way it's worded. It should say that your string didn't match the acceptable strings. Side note: python is case sensitive. You would get the same error if you type it in lowercase.
