Update src/streamlit_app.py

src/streamlit_app.py

@@ -160,7 +160,7 @@ def convert_dictionary(original_dict, mappings):
             new_key, transform_map = mappings[key]
             
             # If the value needs to be transformed
-            if value in transform_map:
+            if value is not None and value in transform_map:
                 transformed_value = transform_map[value]
             else:
                 transformed_value = value  # Keep the original value if no transformation is needed