code: def _SGraphFromJsonTree(json_str):
      
      g = json.loads(json_str)
      vertices = [_Vertex(x['id'],
                  dict([(str(k), v) for k, v in _six.iteritems(x) if k != 'id']))
                                                        for x in g['vertices']]
      edges = [_Edge(x['src'], x['dst'],
               dict([(str(k), v) for k, v in _six.iteritems(x) if k != 'src' and k != 'dst']))
                                                        for x in g['edges']]
      sg = _SGraph().add_vertices(vertices)
      if len(edges) > 0:
          sg = sg.add_edges(edges)
      return sg
docs: Convert the Json Tree to SGraph