code: def lanl_graph():
      """Return the lanl internet view graph from lanl.edges"""
      try:
          fh = open("lanl_routes.edgelist")
      except OSError:
          print("lanl.edges not found")
          raise
  
      G = nx.Graph()
  
      time = {}
      time[0] = 0  # assign 0 to center node
      for line in fh.readlines():
          (head, tail, rtt) = line.split()
          G.add_edge(int(head), int(tail))
          time[int(head)] = float(rtt)
  
      # get largest component and assign ping times to G0time dictionary
      Gcc = sorted(nx.connected_components(G), key=len, reverse=True)[0]
      G0 = G.subgraph(Gcc)
      G0.rtt = {}
      for n in G0:
          G0.rtt[n] = time[n]
  
      return G0
  
label_desc: Use image node_id 1 for calling a global function with example usage: lanl_graph() and returns: G0