Update SampleQA.py

SampleQA.py

@@ -57,7 +57,10 @@ def main():
     if st.button("Sample & Predict"):
         prediction = ""
         prediction = predict(question, text)
-        st.success(prediction)
+        if prediction == "":
+            st.error(prediction)
+        else:
+            st.success(prediction)
 
 if __name__ == "__main__":
     main()