Hello, I’m trying to use Helium-4 temperature at 15000 K. I’ve generated the cross section ace file though NJOY and converted it to hdf5 using openmc.data.IncidentNeutron API. And cross section library has been created using openmc.data.DataLibrary class as mentioned in the openmc user documentation page. Now when combing the new library with the existing endfb7.1 library, it just overwriting the existing He4 nuclide in the library. Does anyone have any suggestion on how I can keep both of the cross section files (preexisting He4 and newly generated He4 at 15000 K ) in new combined library?