docstr: Bethe Hessian matrix
docstr_tok: ["Bethe","Hessian","matrix"]
imports: import pytest
  import networkx
  from networkx.generators.degree_seq import havel_hakimi_graph
label_desc: Use image node_id 2 for calling the TestBetheHessian obj's underlying member method code with example usage: obj.test_bethe_hessian() without return types