def subsystem_to_dot(subsystem):
clone_links = clone_mets(subsystem)
g = Graph(name=subsystem.id)
if subsystem.get_param('CLUSTER_SUBSYSTEMS'):
g.cluster = True
style = subsystem.get_param('SUBSYSTEM_BORDER_STYLE')
g.add(AttrStmt('graph',style=style))
for rxn in subsystem.reactions:
g.add(reaction_to_dot(rxn))
g.add(AttrStmt('graph',label=subsystem.name,
fontsize=subsystem.get_param('SUBSYSTEM_FONTSIZE')))
if clone_links:
g.add(clone_links)
return g
