Filter at the correct time

zenius.py

@@ -169,9 +169,9 @@ if __name__ == "__main__":
     seen_cats = set()
     categories = args.categories
     while categories:
-        for url in {cat for cat in categories if cat not in seen_cats}:
+        for url in cat:
             found = mirror(url, args)
             seen_cats.add(url)
         if args.recurse:
             print(f'Recursively fetching categories: {list(found)}')
-            categories = found
+            categories = (cat for cat in found if cat not in seen_cats)