Update TLDR.py

TLDR.py

@@ -70,7 +70,7 @@ def update_mainTLDR(buttons_to_add, paper_list):
 
     # Check if any categories are selected
     if buttons_to_add:
-        for i in range(length(buttons_to_add)):
+        for i in range(len(buttons_to_add)):
             print("Used categories:", buttons_to_add, flush=True)
 
             # Generate a Markdown object for each selected category