Code Block List - Not Working

Hi Complete newbie here, just trying to create a simple renumber script and I was hoping someone could explain a concept for me around code blocks… I know I can create a simple list by using a code block and entering the syntax for example: 0…2; If I do this in a blank script it works, if I do it in the script I am attempting (already has other nodes in it), it doesn’t work. It returns null. I haven’t connected it to anything yet, so I am just talking about the code block itself… so what is the rule I am missing that is preventing an output? Can other nodes stop this simple action?

 

Nevermind, I turned off automatic and I didn’t realise you have to hit RUN everytime, I though that was just to run the script in Revit.