update app.py

app.py

@@ -25,7 +25,7 @@ if st.session_state.ind:
     st.write(question)
     st.text_input("Write your answer here", key='student_answer')
 
-    if student_answer:
+    if st.session_state.student_answer:
         text = st.session_state.student_answer + '</s>' + answer
         res = pipe(text)[0]['label']
         if res == 'correct_answer':