code: def setup_class(cls):
      cls.path = nx.path_graph(7)
      cls.directed_path = nx.path_graph(7, create_using=nx.DiGraph())
      cls.cycle = nx.cycle_graph(7)
      cls.directed_cycle = nx.cycle_graph(7, create_using=nx.DiGraph())
      cls.gnp = nx.gnp_random_graph(30, 0.1)
      cls.directed_gnp = nx.gnp_random_graph(30, 0.1, directed=True)
      cls.K20 = nx.complete_graph(20)
      cls.K10 = nx.complete_graph(10)
      cls.K5 = nx.complete_graph(5)
      cls.G_list = [
          cls.path,
          cls.directed_path,
          cls.cycle,
          cls.directed_cycle,
          cls.gnp,
          cls.directed_gnp,
          cls.K10,
          cls.K5,
          cls.K20,
      ]
  
imports: import pytest
  import networkx
  from networkx.algorithms import approximation
label_desc: Use image node_id 1 for calling the TestAllPairsNodeConnectivityApprox obj's underlying member method code with example usage: obj.setup_class(cls) without return types