Update app.py

app.py

@@ -148,6 +148,10 @@ def start_test():
 
 def next_step(prev_level, user_answer, question_text, passage_text, start_time, user_id):
     global question_count, used_texts
+
+    if user_answer is None or user_answer == "":
+    return "⚠️ Please select an answer!", passage_text, question_text, prev_level, None, "", True, start_time, user_id
+
     question_count += 1
 
     end_time = time.time()