code: def setup_class(cls):
      G = nx.DiGraph()
      edges = [
          (1, 2),
          (1, 3),
          (2, 4),
          (3, 2),
          (3, 5),
          (4, 2),
          (4, 5),
          (4, 6),
          (5, 6),
          (5, 7),
          (5, 8),
          (6, 8),
          (7, 1),
          (7, 5),
          (7, 8),
          (8, 6),
          (8, 7),
      ]
      G.add_edges_from(edges, weight=2.0)
      cls.G = G.reverse()
      cls.G.alpha = 0.1
      cls.G.evc = [
          0.3289589783189635,
          0.2832077296243516,
          0.3425906003685471,
          0.3970420865198392,
          0.41074871061646284,
          0.272257430756461,
          0.4201989685435462,
          0.34229059218038554,
      ]
  
      H = nx.DiGraph(edges)
      cls.H = G.reverse()
      cls.H.alpha = 0.1
      cls.H.evc = [
          0.3289589783189635,
          0.2832077296243516,
          0.3425906003685471,
          0.3970420865198392,
          0.41074871061646284,
          0.272257430756461,
          0.4201989685435462,
          0.34229059218038554,
      ]
  
imports: import math
  import pytest
  import networkx
label_desc: Use image node_id 1 for calling the TestKatzCentralityDirected obj's underlying member method code with example usage: obj.setup_class(cls) without return types