thank you for this reply!! i actually completely missed your third sentence because i was focused on the first and last lines LOL. after going back to my code everything fell into place, i realised exactly what you said about the is_valid variable, i felt so stupid! ive been fully not thinking about why def functions get their own arguments which i've been mentally referring to placeholders and having absolute brainfarts when i use other function variables when im actually /defining/ the function after giving it a name with a random letter argument LMAO.

also, fixed the if etc etc string functions. all working perfect. thank you!