Export/write inside external blend file

It is actually possible to write blender data (actions, mesh, object etc) to external file with this:

bpy.data.libraries.write(filepath, data_blocks)

But this delete all the data not in data_blocks variable. A practical usage is like to make a different file library to update in production without save a single blend file for each or do the append from the library.

A reverse append. I hope there is an idea to do this in the future Assets Manager.