Update app.py

app.py

@@ -62,6 +62,9 @@ class MockOpenAI:
    )
 
     class Chat:
+        if 'toolbox' not in st.session_state:
+    st.session_state['toolbox'] = {}
+        
         def __init__(self, mock_openai: 'MockOpenAI'):
             self.mock_openai = mock_openai