code: def setup_class(cls):
      cls.null = nx.null_graph()
      cls.P1 = cnlti(nx.path_graph(1), first_label=1)
      cls.P3 = cnlti(nx.path_graph(3), first_label=1)
      cls.P10 = cnlti(nx.path_graph(10), first_label=1)
      cls.K1 = cnlti(nx.complete_graph(1), first_label=1)
      cls.K3 = cnlti(nx.complete_graph(3), first_label=1)
      cls.K4 = cnlti(nx.complete_graph(4), first_label=1)
      cls.K5 = cnlti(nx.complete_graph(5), first_label=1)
      cls.K10 = cnlti(nx.complete_graph(10), first_label=1)
      cls.G = nx.Graph
  
imports: import pytest
  import networkx
  from networkx import convert_node_labels_to_integers
  from networkx.utils import edges_equal, nodes_equal
label_desc: Use image node_id 1 for calling the HistoricalTests obj's underlying member method code with example usage: obj.setup_class(cls) without return types