code: def build_wheel_graph(num_nodes):
      
      # The easiest way to build a wheel graph is to build
      # C_n-1 and then add a hub node and spoke edges
      graph = build_cycle_graph(num_nodes - 1)
  
      cycle_graph_vertices = graph.get_all_node_ids()
  
      node_id = graph.new_node()
      for cycle_node in cycle_graph_vertices:
          graph.new_edge(node_id, cycle_node)
  
      return graph
docs: Builds a wheel graph with the specified number of nodes.
         Ref: http://mathworld.wolfram.com/WheelGraph.html