How to create a Resource from a file I loaded with a custom ParaView reader?

I am getting closer to it, as shown in How to import a .vtu file programmatically? - #2 by CsatiZoltan
Is there a way to extend (subclassing or other way) smtk::markup::Import (the VTK session cannot import a .vtu file, as I noted in my other post) instead of modifying the source code (that way, I would have to be up-to-date with the SMTK git repo)?