Update app.py

app.py

@@ -100,7 +100,7 @@ def generate_prompt(
     characters = get_random_items(load_candidates_from_files(character_files) if character_files else [], 1)
     dtr_candidates = get_random_items(load_dtr_from_huggingface() if dtr_enabled else [], 1)
 
-    number_of_characters = ", ".join(selected_categories) if selected_categories else [])
+    number_of_characters = ", ".join(selected_categories) if selected_categories else []
 
     tags = {
         "number_of_characters": number_of_characters,