Spell as Display?

[Eric Charles]

My use case is running a spark paragraph with println(s"""%sigma 
$graph""") that is supposed to call my spell and display the graph.

Is there a way to use existing spell module as display systems?
There is in result.controller.js#324 
heliumService.executeSpellAsDisplaySystem(type, data) which makes me 
think there is a way to achieve this, but I don't get there

I tried to define in helium folder the spell as visualization, but this 
does not work.