message: check if reachable object type is method when adding overriding methods to their successors
  Summary: Still check if the type is a method before adding overriding methods as successors.
diff: @@ -268,6 +268,7 @@ class CombinedGraph(object):
  # find child in reachability graph, then build edge
  method_child = self.reachability_graph.get_node(child.name)
  for pred in method_node.preds:
  + if pred.type == ReachableObjectType.METHOD:
  self.reachability_graph.add_edge(method_child, pred)
  self.nodes = self.reachability_graph.nodes
  