[igraph] nested graphs

[Parker, Rachael J]

I am trying to create a directed graph from a circuit netlist which has a 
hierarchical format illustrated below.
This would seem to want a graph of graphs arbitrarily deep:

cell1 = graph()
cell2 = graph()
cell3 = graph(cell1,cell2)
cell4 = graph(cell1,cell1) # note, 2 instances of cell1

I know you can have a graph as an element in another graph but can't figure out 
how to expand this graph (flatten) for visualization.

Any pointers would be greatly appreciated.
Best,
Rachael Parker

 
.SUBCKT  cell_name_1
instance_id_1 primitive_cell
instance_id_2 primitive_cell
...
.ENDS

.SUBCKT  cell_name_2 
instance_id_1 primitive_cell 
instance_id_2 primitive_cell 
...
.ENDS

.SUBCKT  cell_name_3
instance_id_1 cell_name_1 
instance_id_2 cell_name_2 
...
.ENDS

.SUBCKT  cell_name_4
instance_id_1 cell_name_1 
instance_id_2 cell_name_1
...
.ENDS