TypeError: object of type 'NoneType' has no len() - what do it mean?

[leviathan54]

ok guys - i figured it out. It wasn't an issue with my code. After spend way too much time on it, it turns out you need to have the spreadsheet closed in order to intereact python with the spreadsheet using openpyxl.

Apologies if i messed any of you around but I am grateful for your help. I'm learning and this is new to me.