def __init__(self, *args, **kwargs):
super(TopoSpec, self).__init__(*args, **kwargs)
app_manager.require_app("ryu.topology.switches")
CONF.register_opt(StrOpt("spec_path", default="spec/mininet.yml"))
self.graph = nx.Graph()
self.spec = Spec.from_yaml(CONF.spec_path)
self._thread = hub.spawn_after(3, self._compare_spec)
