Update app.py

app.py

@@ -251,7 +251,7 @@ def handle_userinput(user_question: Optional[str]) -> None:
     if user_question:
         # Clear any existing related question buttons
         if 'related_questions' in st.session_state:
-            del st.session_state.related_questions
+            st.session_state.related_questions = []
 
         async def run_search():
             return await run_auto_search_pipe(user_question)
@@ -376,7 +376,7 @@ def main() -> None:
                 st.session_state.chat_history = []
                 st.session_state.sources_history = []
                 if 'related_questions' in st.session_state:
-                    del st.session_state.related_questions 
+                    st.session_state.related_questions = []
                 st.toast('Interactions reset. The next response will clear the history on the screen')
 
         # Add a footer with the GitHub citation