evaluating /obj level shop_materialpath in python

[Neon Junkyard]

I have an fbx subnet with a bunch of different models that Im object merging into a separate geo network with wildcards to grab all the file nodes in the fbx subnet, and enabling create path attribute in the object merge

I need the shop_material path to correctly point to the corresping fbx material that was created, and while most objects are read in with the shop_materialpath attribute correctly, the houdini fbx importer will interpret the material assignment at the object level depending on how the model was prepped, so the resulting shop_materialpath from the object merge is missing.  The textures and materials are there at the object level (in the fbx subnet) but the shop path is wrong, and thus textures break in the object merge. 

so I need in a python sop to run a loop over each prim, eval the obj level shop_materialpath parameter from its path parameter (i.e. its source geo network in the fbx subnet) and append that string to the current geo shop_materialpath for the missing prims

thanks