Update app.py

app.py

@@ -67,9 +67,9 @@ else:
     with st.spinner():
         if st.button('Generate Graph'):
             try:
-                # Ensure the question is a string
-                if not isinstance(question, str):
-                    st.error("The question input is not a valid string.")
+                # Ensure the question is a valid string
+                if not isinstance(question, str) or not question.strip():
+                    st.error("Please enter a valid question in the form of text.")
                 else:
                     # Use TAPAS model to process the question
                     result = tqa(table=df, query=question)