A follow-up on your suggestion. In wrapping/CMakeLists.txt, I have modified ITK_WRAP_PYTHON_LIBRARY_IMPORTS. It works if RTK is loaded (no LazyLoading or something loaded the module beforehand). If the first RTK attribute is in one of the imports and lazy loading is on, ITK does not know the symbol. I have found a work around with __init_module__.py, see
What do you think of this “solution” to add the new attributes to the lazy list? It seems a bit too low level but I haven’t found a better solution… Suggestions are welcome!