> Can our group write a custom Python script code to convert Mappa output (Topic Map Engine) into object graph data?
Well, Mappa writes XTM (XML), CTM (syntax which is editable by humans easily)
and JTM (JSON). Either you convert any of the formats into the target format
or you can write your own serializers.
Mappa provides also a plugin system for (de-)serializers, the XTM
serializer  defines for example the following entry point:
xtm = mappaext.xtm
The plugin-system isn't documented very well, but basically it expects
a unique name (xtm in this case) and the module where a function
"create_deserializer" could be found.
In case of questions, don't hesitate to contact me.