Looks like you are asking for a list item before a list exists.
Make sure your list is present before trying to select an item from it.
The empty text block is not a list.
Let me guess... are you using TinyDB?
And valueIfTagNotThere is an empty string?
It would really help if you provided a screenshot of your relevant blocks, so we can see what you are trying to do, and where the problem may be.
To get an image of your blocks, right click in the Blocks Editor and select "Download Blocks as Image". You might want to use an image editor to crop etc. if required. Then post it here in the community.
Taifun
Trying to push the limits! Snippets, Tutorials and Extensions from Pura Vida Apps by 
Taifun.
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Where is your Answer List ?
Please do not take photos of your blocks, those are almost unreadable
Do it like this
Please!
Taifun