code: def setup_class(cls):
      deg = [3, 2, 2, 1, 0]
      cls.G = havel_hakimi_graph(deg)
      cls.P = nx.path_graph(3)
  
imports: import pytest
  import networkx
  from networkx.generators.degree_seq import havel_hakimi_graph
label_desc: Use image node_id 1 for calling the TestBetheHessian obj's underlying member method code with example usage: obj.setup_class(cls) without return types